I'm actually surprised this wasn't modded for being a 1-Liner in the LMF that is very sarcastic and relatively pointless. TB has been playing this deck longer than most people have and knows how to modify a deck to beat what he needs to beat, ontop of probably just outplaying them anyways. As I have no idea who you are and didn't even realize you were a member here until today, what have you contributed to the format lately?
Terminate vs. Smother vs. Snuff Out vs. Your_Removal_spell_of_choice_01:
Personally I would play Smother for reasons of it being easier to cast, because you don't have to leave up 2 colored sources. Pro-Red can be a huge deal if you are running Terminate, but if you're running it knowing there is going to be a lot of Sword and Jitte weilding Silver Ka-Nig-Its, why the hell are you running Terminate? That whole thing should be a metagaming desicion. On a pure vs. the format level though, I don't see many reasons one would be better than the other. They're both pretty even in this format and basically up to your personal preference and metagaming desicions. Far as Snuff Out, it probably would work very well but, I'd actually like the option of being able to realistically hardcast my removal. I can't see many reasons why I'd pass a turn and leave 4 mana up.