I've got a Garmin Edge 810 and it's really good, but it all depends what you want it to do.
As well as recording my rides and uploading them to Garmin Connect (similar to Strava I guess), it gives me navigation on pre-loaded routes. Basically you can plot a route on the Garmin Connect site by marking points on a map just like Google Maps, then upload it to your device. It will then give you turn by turn navigation instructions. The base maps are pretty rubbish, so it's well worth spending £30 on a UK mapping SD card.
I tried it in the woods last week having pre-loaded a route, but as it didn't recognise any of the tracks as roads, it didn't navigate me. I still recorded my ride tho' so it still got added to my monthly total.