All depends on the situation. If you're just going to buy an unlocked phone outright, I'd go through Apple. if you're trying to do EIP or Apple's payment plan, I'd do T-Mobile online. Apple's site specifically states if you want to tie it to T-Mo, you have to do it in store to activate. I'm gonna do mine through the T-Mo website. My brother got his 7 Plus through the T-Mobile website on pre-order day and delivered launch day.