I always order on VZW site. You get instant rebate that way and you also have VZWs great return policy etc.
If you have an issue with the phone you pretty much call them up and troubleshoot for a few min then they overnight you a new phone.
Also on VZW site use code FREEOVERNT (I think that's what it is) for free overnight shipping.
Can't beat that IMO
I would never buy through a 3rd party but, that's just me.