I owned a Nova SP (18.5" ghost ring) from about 2001-2005. I currently have a Nova (28" bird gun).
I put probably 3-4000 birdshot through the first one, about 350 through the bird gun so far (acquired last year for free).
The Nova functions well as a design. Solidly built. Never had a malfunction with bird buck or slug I can remember. With ghost rings, and Remington Sluggers from the prone, out of the box I could headshot a silhouette at 100 yards on demand. My only issue was the 3.5" receiver made it about an extra 1/2" longer than it really needed to be. It's nice having the option in the event I ever wanted to shoot down UFOs, incoming V-2s, geese at super high altitude, or possibly bears in Alaska, but for 95% of shotgun work the Super Magnum rated receiver was overkill.
The original Nova stock fits me, however, not everyone is me (5'9", 230lbs), so the SuperNova came along. Both work fine. If the guns fit you, you're unlikely to have a serious issue with them. If you ever find the Aguila mini-sized shotgun rounds, the Nova will feed them. I acquired six (all I could find) and had zero feeding issues. Some guys, usually hunters, bitch that the fore-end rattles, but if the gun is in your hands where it should be, it doesn't. And what detectable rattle there is, is very minor (no more noise than you walking).
While I currently use an 870P for Serious Purpose shotgun use, that is mostly because we issue 870s at work for LL and I believe in commonality of training. The Nova should serve you well.
Edit: due to the huge numbers of Remingtons and Mossbergs out there, accessories are harder to find for the Nova, but any "generic" light mount made for either should fit the Nova if it mounts to the mag tube, etc.