Another +1 for Coopers PET bottles.
I originally got a counter-pressure bottle filler to use with swing-top glass bottles but it always seemed to make a mess, no matter how careful I was.
In the end, after buying a bunch of these PET bottles and using them in conjunction with the carbonation cap I already had, I wondered why I”d bothered with the CPBF at all.
It may have been worth persevering if I did a lot of bottling, but I keg 95% and just use bottles for the litre or two left in the fermenter when the keg is full, or for giving bright beer to friends. And, for that, these are perfect.