I was using prevacid and loved it. Prevacid worked great for me but several months after I started using it, my insurance changed and would only cover prilosec OTC. I've been using prilosec OTC (30mg) once a day for years now, and it works just as well as the prevacid did. The only thing I've noticed between the two is that prevacid will last a little longer if I forget to take it one day. I could have easily taken the prevacid every other day and had the same relief. If I forget the prilosec however, I notice it by the end of the day. On the occasion that I forget to refill my prilosec and run out of it, I'll take zantac just to get relief through a weekend or couple of days, but I don't think it works nearly as well as prilosec does, even though they're both over the counter.
My stepdad recently just tried a new one, Zegrid OTC (??) and said he didn't think it worked as well as prilosec.
Hope this helped, good luck!