I used a Polar CS600x and more recently an RCX5 (for the multi-sport stuff). Both units worked beautifully. Initially I used the G3 GPS unit and upgraded to the G5 when it was released (G3's battery life was limited to around 3hrs on a rechargeable penlight battery vs. around 20hrs on the G5). They were both great, I loved the fact that the RCX5 would read HR whilst swimming as well. I'm quite forgetful so having to remember one extra item every time I rode became a pain in the ~ss. Having to remember when last it was all charged was also a problem. Although the units themselves had seemingly endless battery life, the fact that the memory in either unit was very limited became a problem for me as well. I've subsequently changed to the Garmin Edge 510 and Forerunner 910XT. Although both need charging as does the Polar GPS unit, at least there is some sort of meter telling one how long to go before losing power.I also have one less thing to forget. The Polar units above were my third and fourth Polar products and I must say, although the last two had user changeable batteries, I do not miss having to either make an appointment with the guys in Midrand to get repairs and other maintenance done or the alternative of taking it into a dealer and waiting a week. Garmin has sorted this out very well. After all of this, I never had a software issue with Polar in all the years I used one, not the same for Garmin. I resisted the move to Garmin for ages after loads of "Garmin pressure" from my friends. Having eventually made the move though, I think the total experience with Garmin vs. Polar has converted me for the foreseeable future. I still miss lots of stuff about the Polar units though and am jealous when I see my wife wearing my RCX5 when she heads off on her run every morning...
