I used Avent with DD, purely because I had expected to BF and when that didn't work and I desperately had to get bottles upon leaving hospital, the local Priceline only had a decent range of Avent bottles/breast pump/steriliser etc, TT they only had replacement teats.
I found them really great, the leaking I solved by using a flat terry-cloth nappy (mum bought me 2 dozen despite my insistence that I was going to be 'lazy' and use sposies!) draped over DD's shoulders as a sort of bib (but covered from ear to ear so mopped up those little leaks and spits).

My friend had her little boy 8 weeks before I had DD and used TT bottles, the booby-shaped ones (lol I assume the Closer to Nature type) and her bub had no end of trouble feeding... turned out the teats were just too big for him and kind of obscured his nose while he was feeding, so he choked a whole bunch, if you get what I mean?? She swapped him onto different bottles with a more slim-shaped teat and he could breathe and suckle, problem solved (well, not his awful reflux and alleged lactose intolerance, but he could actually swallow).