My daugher is now nearly 22 months old, so we're no longer using bottles. But for the first 15 months of her life (and exclusively for the first year of her life) we used Dr Brown bottles for her.
Having read reviews on various websites, I had registered for these bottles and received a few packs at my baby shower. However, I had also received other brands... so I had a good handful of bottles to try!
Unfortunately, my daughter had a pretty bad case of reflux as an infant. So, knowing that Dr. Browns bottled claimed the following -
-- Patented system reduced colic, spit-up, burping and gas --
... these were the bottles we ended up using out of the bunch. They truly DID help with her spitting-up. If you're looking for a miracle product that will take away all spit-ups and reflux, you will definitely not find it... my daughter definitely still had spit-ups, vomits and pain. But when we switched bottles to try, she most definitely had MORE of the above. So, Dr. Browns really did lessen the symptoms.
Having said that- there certainly are nagatives on this product. We don't own a dishwasher, so all bottles and parts had to be washed by hand. And these particular bottles have a LOT of parts! The bottle, the nipple, nipple ring, vent inserts (the yellow/beige part), the vent reservoirs (the long tube) and it comes with a travel disk (so it doesn't leak if you place in diaper bag) and a cap. All of these parts were really a hassle to wash, and I had WISHED my daughter could take another bottle due to this. If she didn't have bad reflux, I would have used a bottle with different parts. BUT if your child does have reflux/spits/gas... even though the parts are a hassle, the bottle is worth it. And speaking of bottle parts, you can get the nipples in different sizes- they have a preemie nipple, level 1 (newborns), level 2 level 3, level 4 and Y-Cut (for thick liquids). There are also different sized bottles (4 ounces & 8 ounces, wide bottles.. and "normal" bottles).
We paid $12.99 for a 3 pack of 8 ounce bottles. We never had to replace bottles, but DID have to replace the yellow vent parts, as they tended to get "icky" after several months of use.
In closing -
I definitely loved these bottles because they lessened my daughters reflux symptoms- and for that, they were extremely worth it to us. Had she NOT had reflux, however, I would not have used these.