Yes, I agree with pretty much everyone else on here. Prestige is the thing that counts, let's be honest. Prestige is THE most important thing when choosing what university to go to. Obviously.
Seriously OP, go where you'll be happiest. If you'd prefer somewhere that's a bit calmer, perhaps a bit more of a bubble, go to Bangor. If you want a busy city life, go to Bristol. Have you visited both universities? If not, I suggest you do so as it'll really help give you a feel of each place.