I have had my powertap for exactly a year now and I can honestly say it was the best money I have spent on triathlon, even more so that the actual tri bike.

My vote goes to the PT.

What part of your training do you think a PT would help you with? 

A PT will help you know what you did and it will help you do the correct workout, but it doesn't make up for things like a poor plan or lack of miles.

I have a quarq, my wife has a wireless PT we're both very happy with our respective choices. 

Agree with the main points the others have made.  It can be worth it if you take the time to understand how to properly use it and you're the type who enjoys digging into the data.

It absolutely is not necessary though - plenty of really fast dudes and dudettes out there who train only by RPE/HR.   Key to getting faster is training more and training smarter - this can be accomplished with or without a PM. 

First, your experience stinks for sure.  I would hope that CycleOps steps up and fixes things for you.   That said, I'll echo the PMs and other posts you have seen.  My (wired) PT is still working perfectly after 6+ years.  I have not had to deal with CSRs about the PT, but have with my Cycleops fluid trainer.  My experience was painless and they provided what I consider top-notch service.  While your experience raises a red flag, numerous other stories I have heard about are more consistent with my experience.  I would not hesistate to buy a PT again.  In fact, it would still be my first choice among power meters.

I've had a PT for two years (training only, not used when I race), and very happy with it.

One warning though -- I find that I train harder with the power meter than I otherwise would (chasing numbers), which has put me in holes that take time to get out of (ie., recover).  Important to listen to your body, even when using a PM.

Another caveat -- My best IM bike ride (relative to the field) occurred when training purely by RPE.  So, while I prefer to use a PM, it hasn't made me much/any faster for my A races than I was when training by feel.

In addition to what's already been written, I power because it gives a fixed point of reference.  Yes you can train with HR but it doesn't show you how much progress you've made over time.  Or flip that around -- when I was injured this year, I could see how much I lost off my normal power numbers.

This sounds like two different issues.  You can use your choice of computer with the ANT+ wireless PT, same as Quarq.  I can't speak for the LYC but I've used the Joule 2.0 and a Garmin 310xt with no issues.  As for the PT hubs, they will eat alkaline batteries in a couple weeks just like you said, but the silver oxide batteries last me a year or so.  The battery packaging usually isn't obvious which kind it is unless you read the fine print, so beware of that.

I'll start with one:  Price

There's more, though.  All the systems available have their plusses and minuses.  Figure out which things are more important to you and you'll find the power meter best fit for you.

I realize not everyone will agree with this, but...

IMO, a PM doesn't provide much benefit when used with a trainer.  I've been using a Kurt Kinetic trainer since before I got my PT and still use it without the PT.  On a decent trainer, speed is a very good stand-in for watts.  The mapping between the two isn't linear, but it's close enough around FTP for government work.  (Situation would be different if you were working on maximizing power during short bursts.)

For outside riding the situation is completely different, of course.

Just my two cents!

Agreed. And I'm very happy with my Quarq.

For me it was the exact opposite.  I wasn't pushing hard enough on the trainer before I got the PM.  A good bit of my problem was a lack of fans to help me stay cool, but I was also not going hard enough. 

I see your point about using speed, and could probably switch to that now.

Also consider that speed goes up by a curve on a number of trainers (in relation to an output). Not a straight line. Smaller changes in speed when going faster can be rather significant differences in power. Going from something like 24.x mph to 30 mph on mine literally takes twice the power to do. On a smaller scale, I can see 30 watts (or a bit more) difference for some intervals when there is less than 1 mph change. I want to say 50 is possible, but that would just be winging it. Anyway, that's a very significant difference. The power values I get also translate to outside well. Others may have to scale it a little, but you still have something to go with.

And even with all that, it's still a tool. I use it to push in training, and more as a guide to RPE when racing. Not everyone needs that.