I use the vest whenever I ride my bike, whether it's street or dirt. I actually wear it under my Jacket for the extra protection it gives. It's actually a very comfortable vest to wear and almost feels like a seatbelt, sturdy yet flexible. It does get a little warm, which is nice on the the cold mornings, but is sometime a little too warm when having to work. The biggest downside is that it is not a real back protector. It does not limit flexing and is not very tight at the bottom, so it can move around. One other thing I found is that it starts to stink a little, kind of like a men's locker room, but that could be me as well :) Bottom line is that I like wearing it, because it feels safe and it's comfortable enough to wear all day.
Park City, UT