The Forerunner is essentially an Edge 500 in watch form, but with more besides.
Catering for up to five bikes (each with separate identities and relevant power/cadence/wheel size differences if necessary) it will also capture your data for swims (pool and open water) and running (with optional FootPod).
The screen shows up to four data fields. Power it up, switch on and be sporty for up to 20 hours. Wear it or mount it using the foam bar mount (a twist mount is coming, say Garmin).
You can plan a route and upload it to your computer, then watch and follow the breadcrumb trail. While not as good as mapping, it does enable you to navigate less well-known routes with confidence.
The dongle lets you download ride data and Garmin Connect turns your data into maps and graphs, dissecting your route and performance, including heart rate and calorie use.
The 910XT will work with any ANT+ enabled power meters from Quark, SRM, PowerTap and Garmin’s Vector (when it arrives).