We are having the same issues. I haven't switched to the Dr. Browns bottles yet as i have tons of Avent and can't afford to switch and I am considering going to Gerber Soothe. The Zantac works and it is definately necessary to keep the baby upright after eating. It eliminates a lot of spit up.
That is exactly what I purchased. I only got 3 to see how we would like them and we have just continued to rotate them & have found with the 2 playtex ventairs that we already had we have enough.
I had also started out with Avent and had 8 bottles, and pump. They now sit on top of the microwave unused.