I had horrible lag ever since I got my vibrant from market, web, email everything. I even thhought about returning it, BUT I solved my problem(at least mine). I was at t-mobile vibrantforum and one post saying that factory reset will fix this problem. I gave it a try, and BANG! My phone is lag free. If you have lag problem, give it a try. I know its pain in the a$$ reinstalling all the apps, but having lag all the time is much bigger pain in the a$$. Also, I had trouble getting decent 3g signal, and I unchecked data roaming, and I am getting much better 3g signal too.