well from a financial stand point... there is no choice... BUSA... it's a year newer 2k Less miles... $500 less... and you KNOW how it was maintained... it's the hands down choice...
from the riding standpoint...
you really need to figure out what type of riding you want to do... track days on a busa will be more of a challenge than on the R1 if that's something you wanna do... but commuting, long trips, and daily riding would be more comfortable on the busa I'd imagine.
R1 is a gorgeous bike... and obviously a great bike... but imo... the Busa is a better buy