Having shot 500s for 9 yrs now, I feel well qualified to comment. Currently, I have an 8 3/8" and a 6.5" PC model.
I'm sure the Ross gun is a fine item but w/o the compensator (yeah, many doubt its effectiveness) and the much lighter weight, it will kick significantly harder using the same ammo than the much heavier 7.5" model with its additional advantage of muzzle forward weight which will reduce muzzle climb.
The Ross' primary advantage if you want to call it that and I don't is the faster twist which makes stabilizing the monster 600-700 gr slugs more effective. I have no interest in those slugs, higher recoil with no advantage other than saying you shoot them. A 440gr hard cast will, in many cases, penetrate a cape buffalo from end to end, you need more penetration than that? I don't think so.
Don't reload? Well...unless you intend for it to be a safe queen or like spending obscene amounts for factory ammo, you DO need to reload. I can load quality hard cast slugs for less than 55 cents a round vice $2.50-3 for factory ammo and I can tailor the ammo from dinky to nasty. Don