You should really specify either PvP or PvE (or mention otherwise). Still, you're leaving out some better snipers in favour of popular choices. For PvE, the answer is Blackhammer. You could argue Icebreaker too, for cheesy stuff like heavy ammo glitch. For PvP, there are a few options. For high impact, definitely The Supremacy. Its stats are simply superior to everything else in its class. For other snipers, I'd say Prudence II. You could also argue for Praedyth's Revenge due to its high stability, or Patience and Time (although the default scope is not my favourite). There are other good snipers, but just based on raw stats, these are the best.