You really press for that BeagleBone don't you? haha. There is something to be said about the cost of each thing though. Isn't the BB more than double the cost of the RPi? And the MK802 is only a little bit less than the BB. Though crazyates they got theirs for 41 shipped. I don't know where they got theirs though.
Availability. At the time I got my BB, lead times on RPis were weeks/months. BBs shipped from stock in days. Plus they're "murrican" F yeah.
Reliability. I'm not interested in being a first adopter for every new whizbangy thing that comes along. I know that new hardware is almost guaranteed to have problems and RPi had its share. I saw some chatter on message boards regarding USB issues with RPi and BFL mining.
Maybe RPis ship from stock in days now and maybe they've worked out the early problems. I don't know.