POLAR 625x vs Garmin? Should I switch?

My 2 cents, as you mentioned many people use Garmin, so since I have not used the Polar I do not have first hand experience with how it operates, but you will probably have an easier time finding people around to answer questions about the Garmin and getting it setup properly.

I use an older Polar S410 which has the same body as the 625 but minus some of the functions.  It has taken awhile, but over time I have figured out how to utilize the most important tools of the unit.  Keep in mind, just because it has a lot of functions, it doesn't mean you have to or even should use them all.

I have had a Garmin 301 for training for a marathon and I liked it's features for running, though for triathlon I prefer the Polar.  I can wear the Polar for a race in all three legs, on my wrist, and get my wetsuit off.  The Polar feels better to me on my wrist vs. the Garmin.  I think for a training device, the Garmin is excellent.  For a racing device, I like the Polar.  Just something to think about before you sell it, probably for a loss and then buy the Garmin.

Being able to upload the data from the Garmin to BT is pretty cool though.  I wish we could do it with Polar.

I actually have both a Polar 710i and a s725x.

I had a Garmin for a short time, but prefered the Polar. Polar gives me everything I need, plus as others have mentioned you can use it during the swim, bike and run. I normally leave the s725x on my wrist to pick up my HR during the swim and run, and leave the 710i on the bike to collect the bike data.

There is nothing wrong with the Garmin ... I just have used the Polar for so long, it is more comfortable for me.

Now if you want to log GPS data, obviously you'll want the Garmin.

I have the Polar S625x right now and seriously thinking about replacing that with the Garmin 310x. Reason is simple... I use a PowerTap which is not ANT+ enabled yet, but it's quite inexpensive to do... I could use the same computer on both runs and bike and collect all data in one place. Don't get me wrong, as a running computer, the S625x is great; as a bike computer, I don't like it (right now I'm using a Garmin Edge 305 on one bike and the PowerTap computer on the other...). Being a duathlete, I could care less if the 310x doesn't register the distance in the water...