Is this a serious query, or just an attempt to get a bite from everyone else?
Look at everyone; look at the role (if you hate heights, don't be a para, if you hate jumping out of a perfectly serviceable boat fifty metres away from the shore on an amphibious landing don't be a marine), look at the history, go along and meet the people. Don't listen to grandad's war stories from 1945; entertaining as they may be they have little relevance for your future. Look at where they're based; if your family lives in Barnsley and you can't understand Scottish accents then don't enlist in the Royal Regiment of Scotland; think about the Yorkshire Reg instead.
There is no "best" inf regiment. Do your research.
Every Tom Mick Taff or Jock will say theirs is the best, the tigers will preen themselves and say we are the toughest roughest. The Guards will modestly mention they are the Queens train set and the Rifles will start strumming over the hill while looking like Sean Bean wit a ETH in both hands.
Disco quite rightly locked this but here's some advice all the same. I've read through some of your previous posts and you need to go away and stop posting tripe on numerous threads. You're not adding anything of value and you seem to be hell bent on asking the same questions over and over again as well as offering unqualified advice.