As a new shooter, you do not yet know the most important thing about shotgun selection. What we recommend is irrelevant. Asking what "the best" is, is also irrelevant. Only you can figure out what will suit you best. Fit is everything, otherwise "the best" shotgun is useless in your hands. Even though all guns are designed to fit the average build, they each have so many different idiosyncracies that add up to guns which feel very different from each other. Location of safety, are you RH or LH, face width, neck length, arm length, height, weight, eye dominance, etc. will all play a part in how you interact with the gun.
The recoil from a pump is very different from that of a semi and from an over/under. You may not handle recoil well, who knows? Even different semi mechanisms feel different.
What I'm saying is you have to handle a lot of shotguns over time, and as you gain shooting experience you will come to know what you like and don't like. That being said, pick whatever floats your boat right now and shoot it lots. If you find you don't like it, sell it and get something else. Or go to a local trap and skeet club and ask to try out various guns (people usually are willing to let others try their guns with permission).
A Nova may on paper seem to be a better gun than say, a Mossberg 500. But you may not like the feel of it, or how it fits in your hand, or where the safety is, or how to load it, etc. You seemed to have success with your buddy's 20 gauge - why not get the 12 ga. model?