certainly my experience of both uk and us magazines would be to go for cycling plus, its aimed for people who enjoy riding, they cover commuting stuff as well as keeping you informed of racing stuff, they test a lot of gear too. It's my favourite, a lot of the US road ones seem to be mostly talk about which pro is changing team, or bicycling which i generally don't rate very much.

I haven't checked out asphalt yet, but i've heard good things, i don't know much about mtb mags or bmx tho, sorry