I can't recommend a Rossi RG, because I've never had the pleasure of shooting one. In my mind, you don't know a gun until you actually shoot it.
However, I do have considerable experience with Marlin. First of all, Marlin is actually 2 companies-the one before the Remington buy out, and the one after. In plain language, Remington destroyed a great company. Their current products suck, are way overpriced, and work better as clubs than guns.
Marlins, big bore Marlins pre-buyout can still be had for decent prices, if you look. The other day I held a 22" 444 that was in fine shape and was under $600, hiding in plain sight on the gun store floor rack.
The pre-buyout guns were hands down, excellent guns. If I couldn't afford a Henry, I'd hold out for a good used Marlin. They are out there, and they are worth the money.