Six of one, half dozen of the other.
The S&W looks more like and AR, has been classified by the RCMP as a 'variant', and is restricted, so no shooting other than at a range. Made of cheap pot metal by a company that makes lookalike airguns with other company's brand names on them. Factory mags re limited to 10 rounds besause S&W make a pistol that uses the same part number. Pistol mags cannot be more than 10 rounds, so there are a bunch of Prohibited devices floating around (the factory 25 rd mags without pins)
The Mossberg is plastic. Cheap. Poorly executed. Looks like hell, IMO. But the factory mags are not limited to 10 rounds.
Really. See the two side by side and decide from there. Look at the Colt too (also restricted, also pot metal) as well as the Ruger 10/22 in an Archangel kit, or the SR-22.
The Archangel kit is plastic, but pretty solid and looks better than the Mossy, IMO. The SR is a Nordic Components shell, built by Ruger and dressed up the way Ruger wanted it, so maybe look at the Nordic kit too, if you have a bunch of AR stuff around, or are looking for a specific look.
The big plus to the Colt or Smith, is that the hand motions match, if you want to practice skills and drills. The 10-22 based guns are bringing a HUGE variety of optional accesories to the table, and the Mossberg is about as cheap as you are gonna get a sorta black rifle for.
Oh yeah. The VTR 597 Remington. Some accessories options, more than the Mossberg, less than the 10-22/SR-22. Not restricted.
They all have pro's and cons. The biggest con that I can think of, that excludes some completely, is the Restricted status, meaning no gophers or bush use.
Good luck!
Cheers
Trev