I used the breastflow bottles and they were great. I worked full time starting 12 weeks after birth and nursed as much as possible, so it was important to be able to switch back and forth every day.
The tops have little squeezy tabs so you can let any milk flow back into the bottle. Of course you can't really save it since it's already been used, but you can reuse it after a pause in feeding. I never felt like I was wasting milk.
The inner parts did crack a bit but only after heavy use (same three bottles used for every daytime feeding). I think if you get a good brush like the Born Free set that uses plastic and foam instead of the Munchkin ones with twisted wire nipple brushes, that will make a difference. I had the Munchkin brush at the time and I think they lasted 6 months each maybe. I had bought the big set (the one with tall bottles too) so I ended up using those tops for replacements. Never did need the big bottle size, because by that time you can use sippy cups.
Anyway, I felt it was definitely worth using, I even noticed her opening her mouth wider after she started using the bottles, so if anything it was helpful for the nursing latch :-)