Ahh, Oompa, it's not a dumb question but unfortunately it's not one you will necessarily get a definitive answer to!
We first started out with Tommee Tippee (notfor any reason other than we'd been bought a TT steriliser, so they fitted!) and we used the smaller bottles at first, which has been mentioned before they were easier to carry and hold while feeding.
We started to have some trouble with them (I can't remember exactly but DD wasn't getting the milk out very well) so we changed to NUK as the teats were the same as the SMA bottles we'd been given in hospital. These were fab, she got on really well with them, until we had to change her milk to stay-down milk (as she had reflux).
We couldn't use the NUK bottles anymore, as the milk was too thick to come out of the teats (poor little thing was sucking and sucking, nothing coming out!). We went back to TT at this point and got some vari-flow teats but it poured out way too fast for her... so we then went to Avent bottles, as we could get a faster flow teat which didn't drown her!
The Avent bottles were superb for her drinking, but we got the super anti-colic (or whatever they're called, the gold box ones!) and they kept leaking in our bag! After swapping them once thinking we had a faulty batch, we had the same problem. Research proved it was a common issue and to do with the super-duper anti-colic system!! - so we took them back again(Mothercare are fab with us, lol) and we tried Mothercare own brand.
These have been absolutely fantastic - with both the thicker stay-down milk, the normal milk she then moved onto - oh and also the thicker 'goodnight' milk too.
To cut a long story short (!!) I think it's, unfortunately, down to trial and error as to which your baby prefers - as friends I know have loved both the TT and had no leakage problems with the Avent!
I would heartily recommend Mothercare own-brand though (they even do ones which self-sterilise which is handy for travelling).
Well done if you got to the end of this post, apologies it's so darn long! 