Hey Dude,
If you've narrowed it down to these 2 colleges then its really simple.
Its only depending on 2 factors.
Type of llb degree you wanna do and the location.

1. Type of llb.
Its either the UK Transfer Degree of 2+1/1+2 or UOL 3+0 which is fully in malaysia.
If you want to do the UKT then you obviously know that Brickfields is the choice

BUT if you are deciding between BAC or ATC for UOL then you should consider it bases on the 2nd factor.
You see BAC and ATC has almost the same track record.
Last year the King's scholar was from BAC and this year its from ATC, the quality doesnt really make a difference.
Its the place you feel most comfortable it.
Check out both institutions and see which one you prefer.
As for the lecturers both colleges have a number of commendable lecturers and a few not up to par but at the end of the day reading a law degree really depends on the effort, time and energy you put into realising where your passion is..

All the best

p/s : Do check out help for the UKT program too. The have a number of top-notch uni's in the uk which they affliate with. such as Manchester, Liverpool, Exeter, Leeds, Sheffield and so on..