HRM/GPS Combo - Polar vs. Garmin

My Polar FT7 has finally died after 2+ years of being used and abused. I've decided that this time around, I would like to get a combination HRM and GPS, and I'm hoping some of you might be able to help me out!!

Because I compete in triathlons, it is very important that the device be waterproof in addition to offering the usual HRM and GPS capabilities. I've narrowed down my options to the Polar RCX5 or the Garmin Forerunner 910XT, though I'd be open to other suggestions!

Polar RCX5
This HRM works in the water. The GPS, however, requires a separate, non-waterproof GPS censor that's worn in an armband. This is slightly annoying for regular workouts and really inconvenient in a racing scenario.
(Note: Polar does make an integrated GPS/HRM that doesn't require a separate censor, but that model (RC3 GPS) is not waterproof)

Garmin Forerunner 910XT
GPS is integrated into the watch. While the unit is waterproof, the HRM strap won't communicate to the watch while in the water. It will still measure my swimming distance, just not my HR/calories. This model is also quite a bit more expensive than the Polar.

So basically it comes down to is it more important to know my swimming stats or to have a fully integrated system without additional censors. And is the integration worth the extra money?

Does anyone have any thoughts on this dilemma or have personal experience with either of these models?? Thanks!!