Philips Avent Naturnah in my opinion is the best choice! Had the first classical Avent bottles and NUK bottles tried and found the first great as well. The NUK bottles I found this cap but eventually just annoying. By chance, I then tried the Naturnah bottles (really only because I found them very visually beautiful) and I must say, they are by far the best! Lying comfortably in your hand, suckers look very similar to breast and my child finds them too! No abdominal pain, barely belching after drinking and no annoying cap! The next child, then there's only Avent Naturnah :-)