I've been making some mashups recently in OpenLayers and find myself naturally favouring OpenStreetMap as a baselayer, I think this is mostly because I like the concept. I realised the other day that I didn't really know why I prefered it, and have played about with googles various base layers, andlong with those of Yahoo and Bing.
Are there any discernible benefits of any of the baselayers that I have mentioned (or any others that I havent)? Do you find any problems with any of them or do you find that your users prefer one above the rest?