I don't own a nova anymore but I used to own one and one of my good friends owns a supernova. I've shot them both and never really noticed any differences. The supernova probably cycles a little smother that the standard nova. But other than that depending on what you are doing with it the nova will be fine. Such as if you hunting and using it in the brush a lot you might not want to use the more expensive one, or if you are going to convert it to a one better designed for home defense. You will probably modify it anyway so if you can save a little money somewhere. Why not?
"No man ever won a war by dying for his country, He won by making the other poor bastard die for his" - General George S. Patton