I wouldnt say Eternal Sunshine is very 'mainstream' either.. but to me, it didnt come off quite as pretentious. IMO, Huckabees is a nice idea, but marred by some atrocious overacting... It tries to come off as cheery and clever at the same time, which really doesnt quite fit the genre. ES stays a bit truer to its idea and less towards pop-cinema. Both movies arent great, but ES is a bit more tolerable.. To each his own I guess.
I'm sorry... I almost always like weird films like this. Just love 'em. Almost to a fault. But you know what? This one just wasn't very good. One of my buddies left in the middle of it, and by the time the rest of us were done with it we wished we had. Good idea, horrible execution.