How is BTG legal as a firm? How much do they pay their associates? What tier is it?

I've heard good things about the firm. Mostly acts for foreign clients. The pay is also comparable (or even relatively better) than other tier 2 firms, such as Bharucha, DSK, Argus etc.

Bharucha pays 13 lpa dsk 12, really?

I think this is not true. Their culture etc seems to be good, but the pay (from what I have read on LI), does not seem to be thaaat great.

Can anyone share their insights as to what the pay scales, work, culture etc is at the Firm?

Pay is quite low for associate levels, less than even T3/boutiques. SA and above make like 10-20% less than T1 pay. You will notice BTG is a little top heavy, this is why. But work culture is good throughout.