M416 is my favourite for Assault but the AEK is good and the F2000 is supposed to be good (particularly close range) but I have not tried it myself as I am using each gun to 350 kills before moving on.
For engi the G36C is the best I have found but the A-91 isn't bad either.
TBH the AK7/M4a1/M16a3 are not too bad really - just get a grip on them and away you go.
The UMP was OP in beta but it is horrible in the real game in my opinion. Accurate enough but so slow firing and not much damage.
The SCAR-H is horrible as well - and it was in BC2! What is wrong with you guys!

(slow rate of fire, not particularly accurate and it has only 20 rounds per clip)
Edited by deleted (Mon 07-Nov-11 23:16:02)