just to shed some light, on the calibre of candidates the big 4 accepts.

I am in the corporate tax service side and my batch have about 13~15 of us...
i don't know about the other big 4 or other lines of service. so I can't speak for the others.

as far as i know, most of my peers have at least a second upper and some have even attained magna cum laude(shall not name names). Its probably not as selective as FO roles in banking but its also not a walk in a park to get an offer with the big 4 corp tax.

Well' i hope this put things into perspective.