I use the Oregon 400t. Since I live in Singapore, I had to get additional maps but it is nice to have a few community generated maps for garmin and I use them.
I use it on my bike to do regular rides around town and occasional short tours to Malaysia. Here is a recent ride
I did on my NWT with the oregon. You can see I mount it on the stem (first picture).
The mount is pretty decent with a lock at the end. the stem should be long enough or else the mount will have trouble with fit. The one on the image is a 80mm stem I guess and it fits just nice. it is not a big deal as you can fit the mount elsewhere. The mount is good for me. I sue 2 sets on 2 bikes and it has been pretty trouble free till now (almost a year). Visibility in strong sun is a bit of a problem. I have to shade the display to read under direct sunlight. I seldom consult the map and when I do, it is probably because I want to find my way and I am probably parked under a tree or so. Accuracy is pretty good (my commute goes through downtown Singapore and I can get a reliable fix). Battery life is alright too. I use rechargeable AA cells and they last about 8-10 hrs. I could as well pop in standard batteries if I run out, so that is neat.
Though not the best solution, I sometimes carry it in my running shorts. It is heavy for running and wouldn't recommend it unless you have a good solution for carrying it. The Nice thing is that the Profiles allows you to switch between different settings quickly for use under different situations.
Overall, I like the Oregon for cycling. It has replaced my Edge 305 and I don't miss the edge anymore.