Out of those two I would pick the BPS. I personally do not like the way the Nova feels in my hand. Side by side comparison of the two makes the Nova seem like a toy. When it is all said and done though, what is most important is that the gun fits you so whichever fits you the best is the one you should go for.
Sporting the Ambusher Layout and the Sprigtail Pirogue by Core Sound Layout Boats. "By the time they see you, it's too late."
I know your looking for a 12ga im sure, I just picked up a 20ga BPS I shoot an a400 extreme at ducks. I fell inlove with this little 20ga shooting skeet with it. Its so smooth and throws up really smooth. I like the nova but I like the BPS a lot more.
Unless you get an older 870 or an older wingmaster they will be really tight especially in pumping and not smooth. I have had a new 870 20ga and it shot well but just did not feel good when pumping. I right now have a brand new 870 wingmaster full high gloss black walnut, best one you can buy. It is not a smooth shooter either. Like I said unless you get a broke in older 870 I think you will enjoy the bps more.