It seems to me that when there is no opposing traffic present most drivers do more of a rolling stop than a full stop (I know I do). I doubt if my rolling stops on the bike have me moving any faster than the average car at the same intersection, it's just more obvious on a bike. I have to say that drivers around my area have never been anything but courteous with me at four way stops when I'm on my bike. If anything they can be polite to the point of being a PITA, waving me through instead of taking their turn - I always worry that there may be another vehicle coming from a different direction I haven't seen yet.
lechwe, not many "boulevard turns" in my part of Michigan so I haven't ridden through one yet but now I'm looking forward to it.