Which Garmin is Best...or other GPS Watch

I have the 205 (which is the 305 w/ out the HRM) and I absolutely love it.

I don't think - from what I've heard - the 310XT is worth the extra money.

I would take that money and put it towards something else...

I took the plunge recently and bought the 305 (mainly because I got a great deal on one). From everything that I have read and researched, the 310xt is "waterproof" but does a shotty job at it. Apparently the GPS signal is very weak and inaccurate in the water, almost defeating the whole purpose. So yea, you can wear it in the water, but will you get the output you desire? Everything I have found points to no.

Hope this helps

You cannot outright vote for one or the other without knowing the situation.

If you train with power, there is a significant advantage in the 310xt.
Extra battery life on the 310 is an added bonus if you race the longer distances.
Finally waterproof is eh at the best, I swim with my 305 in my cap inside a ziploc and have had no issues, plus it actually maps the swim etc.

If you do not need power, the price point of the 305 is much better.

For 80% I would say the 305 is the best bet.

I bought my 305 at an REI scratch and dent sale. They had a table full of GPS units, probably 4 or 5 305 units. Best $50 I spent that day. Just thought I'd mention it as an option if you have an REI in your area.

I'd love to have the new one but I also love my 305.  Not wearing it in the water has never been an issue for me.  I put it on my bike before I get it the water and there it is when I come out.  Not going to look at the time during the swim anyways and GPS wise it doesn't do what I want (but I could do the baggy thing with my other one), and I put it on my wrist as I run out of t2 so it doesn't slow me down.  I know what time the gun went off for the swim, I know what time I started biking, so I can pretty closely figure out my swim until official results are posted. 

So, you want powe?  Then you have no choice between the two.  Otherwise the 305 will save you a ton of money.

Note, when I do practice OWS I just wear a regular waterproof watch and just go by time.

If you plan on anytime using power or anything that has ANT+ go with the 310XT.   I really wanted to not like the Garmin, but I have found it very useful and worth every dime.  The HRM stap for the 310 is lighter and I barely know it's on. 

I had all kinds of workarounds with my polar and have spoken with people that have ones for their 305.  But if you want to not have to figure out how to make the best of what you have, ie settle, then get the 310. 

The 310 is smaller, lighter, more powerful and more useful (ie no workarounds).  So if you can afford it, get the 310.  If it's a money thing, then get the 305 and work around the downsides.

I have the 305 and love it but I don't have a HR monitor while in the water for training and this is what I think the 310 would be good for.  If I could do it all over again (having fore-knowledge of an injury and taking up tri's) I think I would buy the 310 for the HR in the water.  That being said I have done NO research for this product or others like it, it just sounds like a better tool for tri-ing than the 305.

Doing an ironman?  Get a 310xt.

Otherwise, the 305 is awesome.

It really comes down to your needs... if you plan to collect data from an ANT+ power meter, such as PowerTap or SRM, then 310XT is your only option.

The 310XT is water proof, but that said, it doesn't mean that it's designed to collect GPS data in water; reality is that it just can't get a signal lock when you're in the water, so this is really a moot point. The benefit is that you can wear the watch on your arm already collecting HR data, ready for you when you get out of the water and in transition.

Unless you are planning to swin with it and/or use if for ANT+ data, then I see no reason to spend the money on the 310XT, but if you are going to swim and/or collect Powerdata, then the 310XT is an awesome option.

At the risk of beating the horse further, I say 305 unless you plan to bike with power and want it all in one device.

Besides the ANT+ technology, the only other MAJOR selling points that come to mind is the battery life (305 should work for anything ~8hrs or less) and water proof.  IMO, not enough extras to make up for the increased price...but without any info from you (and no training data in your log) I can only guess...

good luck

Just to make things clear about the 310's vs the 305's water resistance:

The 305 is rated IPX7 for water resistance, which means it can be at one meter of water for 30 minutes.

The 310xt is rated to 50m water depth, which is somewhere between IPX7 and IPX8.

However, the heart rate function of both works equally well (or equally poorly rather) underwater, meaning you more than likely won't get your heart rate while you're swimming. The main factor to this is the signal travels very poorly from the chest strap to the unit itself. If you hold your forerunner right up to the chest strap while underwater, you'll pick up the signal, but that's not making swimming very easy.

The water resistance also has nothing to do with the GPS capability underwater. Any GPS unit underwater is going to get very poor, if any, reception to the satellites. Some people put their forerunner under their swim cap to keep it at the surfance as much as possible, but in this case it doesn't matter whether you used a 305 or 310.

Hope that helps a bit, just don't want anyone buying something with the wrong information.

For what its worth to you, the 310xt calculates calories burned based on HR while the 305 does not (it uses weight/pace/distance data to approx, which is waaaaaaaay high in my experience).  I got the 310 based on that, becuase I thought it would work while swimming (putting under myswim cap works well enough though), for the ability to add a power meter at a later date, longer battery life, the "multi-sport" mode, and because it said the GPS signal lock was much quicker/more accurate (though I'm not sure if this is true as I've never used a 305).  I have not been disappointed or regretted it yet.  It is huge though, and with the quick release kit, it sticks out even farther when wearing it on your wrist.  It doesn't bother me and I don't notice the size, but some people might.

If you have to ask then...the 305.

You should step up to the 310 if:
1) You train with power (ANT+ compatibility is needed)
2) You are doing a full Ironman (Additional Battery Life is needed)
3) You like the shape/design of the 310 more than the 305 enough to justify the cost difference
4) You want to be able to wear one watch for the entire race, again, enough, to justify the cost difference
5) You care enough about the fact that the 310 does HR based caloric computations, versus the "dumber" speed based algorithm in the 305

The waterproof nature of the 310 allows you to wear one watch the entire race and keep your total time on track on one watch. Garmin is very clear that it is not designed to gather GPS data in the water. At this time, this is really a limitation on GPS technology, not on a Garmin shortcoming as some imply. The transmittance of GPS signals through water is well, not that great. That being said, I have seen some people get decent, though not great data GPS wise in the water. If you want you can always put your 310 in between 2 swim caps on your head (like the old 305 trick) and get better GPS data.

My 2 cents.

Interesting thread - seems like I know what to ask Santa this year (310XT).

I'm a mac user and I'm running WKO+ via parallels, and obviously I would like to have all my data end up in WKO+. I've noticed direct downloads from WKO+ don't work (something with USB and incompatibility) so I would need an other means of downloading the data first in mac native software, exporting and importing into WKO+. For my powertap data I do this through PowerAgent, but I need to know if I can also do something similar using Garmin training center or garmin connect...Thx. 

i enjoy my 310

it also seems to have a better gps locater.  Mine boots up much faster (maybe 10 sec to get sattelittes).  Also doesn't lose the signal when you go under an overpass or through thick trees (this could be just around LA).

It also looks better which is completely personal...

Unless you are getting a 305 for less than $100 I would just get the new model.  It's not that much more...no lattes for a month and it's yours.

Agree with most everything you said, but to clarify, although the 305 is rated at IPX7, Garmin does not stand behind swimming with the unit.  Yes I know swimming should satisfy this standard, but Garmin specifically states they will not warranty a unit if it has been used in the water. 

Very true - I think the the IPX7 standard assumes that whatever is being used underwater is kept stationary at the time. Most electronics that are "water resistant" are labeled with the disclaimer that buttons should not be pressed underwater as well, because this can allow water past the seals. As soon as you move an object through water, the water pressure against the forward-facing sides of the object increases, as if you're taking it deeper.

Thanks for everyone's responses!

I think I will go with the 305 - I am a couple years (hopefully) out from an Ironman and I am sure that Garmin will have a new toy by then!

i got the 305 w/ HRM from Amazon for $150. great buy !

also recommend the quick release kit for the bike, not necessarily for the bike attachment, but the velcro wrist band is much better than the wrist strap that is stock on the 305.

nothing is perfect, the 305 is really useful.