Is there any payment gateways that are better then NMI? Or does anyone know where I can go to use different or additional gateways?
Check out PayLeap which to me is one of the best or Authorize.net which is probably the most popular.
I always have a difficult time answering the "which is better" question, since 'better' can mean completely different things to different people and needs. What specifically are you looking to compare against NMI?