We started off combination feeding, although my son is not completely formula fed.
We tried Tommee Tippee closer to nature bottles, but he could not latch onto them at all, and he got very stressed while trying to feed, because he dribbled most of the milk out!
We have moved him to use NUK bottles and found these brilliant for him.
I have heard a few other Mum's who have said the same thing about the Tommee Tippee bottles, but every baby is different, so it's just trail and error really!