I'm with Virgin Mobile; should I buy Unlocked or Sprint-locked?
I'm just wondering which one, locked or unlocked, will provide me with the easiest process when setting up the S5- or whether there'll be a difference.


If you're buying the phone from the same carrier that you will be using the phone with, there's no difference to you. The only thing that makes set-up hard is if you buy a locked phone from one carrier to use with a different carrier: in that case you need to unlock it first.

Unlocked phones do have a slightly higher resale value, because the next user can use them with any carrier without having to get them unlocked. Unlocking a phone from the carrier typically costs in the region of US$10, and you can do it officially (by paying the carrier a fee) or unofficially (in an independent repair shop, or through a third-party website).

There's no advantage to the user of having a locked phone.



To avoid confusion: note that this carrier lock is completely unrelated to the PIN or pattern you use to unlock your phone. It's also completely unrelated to having a locked bootloader. Those are three separate concepts; they just have similar names.