ABA has known about Avent being the worst style of teat on the market for a little while now. I think the bes tis actually the older style ones. you know the type on the cheap bottles you can pick up from junk shops. Just the plain old ordinary narrow long ones.
I alwasy bought these bottles as a cheap EMB storage option but never realised the teats where also a better option. I too used Avent with Evan when he would have EBM. Glenn would take it from anything so I just used what ever was clean & handy, lol.