Best (G)mail experience on iPhone/iPad?

I've gotten by with the stock mail app on my 4S for the past year, but the conversation between Josh and Nilay on the recent Vergecast regarding how terrible both the stock mail app and the Gmail app are for users made me wonder what I was really missing.

I know the Gmail app isn't native and is slow because of that, but what is the best option for iPhone users? I'm going to have this phone for another year at least.