either of the OS 46's are fine engines, the AX has a bit more power and the LA has better fuel economy but both fly great in the tiger 2.
as for the other name brands, i agree super tigre is a close second to the OS but the others, while great engines, do not hold up for the lifetime you'll have an OS if you take care of it. the thunder tigers only last about 5 or 6 yrs, super tigre 10-15 and OS till you or it one is buried.

on the radio choice, i only fly JR and recommend any of their 7+ channel setups.

kc