I say go for the Apple store if they have it in stock.
I bought it at Best Buy, and while Best Buy's official return policy is 30 days, each mobile branch operator makes up their own rules when it comes to returns. I've heard everything from:
1. The iphone is in high demand, so we can't take returns if it has damage (even if that damage was on the phone out of the box)
2. Same as (1), but no exchanges
3. You can only return to original store you purchased from (they give you the run around)
Sure, eventually you can get your return, but you are going to have to file a complaint to corporate and have them call the local store.
Then I took it to the Apple store after all this, and they said "you have to deal with BB since you purchased from there." After some persuasion, Apple finally decided to help me with a replacement. But it wouldn't have been as easy had I just purchased from there outright.
Avoid 3rd party retailers imo.