Got the 810 and 910XT, and have had 800, 310XT and virtually every Garmin device before that. Have also had most of the Polar devices in the last 10 years. The 810 is a fantastic cycling tool, and the full color mapping is great. Many of the MTB stage races are starting to use Gps routes instead if markings, and this device is awesome for that. The Bluetooth integration with my iPhone works a treat and your data is uploaded as soon as your session ends. Really a great device. 910xt is the gold standard for multisport devices, swim, bike and run, and easy transitions between them. It does use the ANT+ key to upload data, so you need a PC to do it, unless you have an ANT+ key for your phone. Suunto is my next favorite because they are great looking and integrate the GPS into a watch you can wear every day. They don't make an integrated swim device though, so that is a gap they need to fill. I have no experience with Bryton, but by all accounts they are nicely out together. All Garmin, Bryton and Suunto devices use the ANT+ standard for peripherals, so their extras like HR, cadence, speed and so on are fully interoperable. Also most power meters will work seamlessly with all of the above. The Polar RCX 3 and 5 are both really fantastic, the only drawback being that the GPS is a separate pod. Benefit is that they are also watches so you can wear them all day. Sadly Polar still doesn't support standard ANT+, so you are tied to their proprietary peripherals for cadence, speed, power and so on.
