I have an LSI Puma in .454 Casull. 16" stainless with fiber-optic sights. It was a gift from a buddy of mine way back in the mid-2000s. It's an absolute hoot to shoot! I've shot it at indoor handgun ranges, and it stops the entire range every time lol.
LSI hasn't made them in years, and I think these are going for a pretty penny today, if you can find them. I imagine the Rossi offerings are probably going to have an effect on that though.
No experience with the Rossi rifles, sorry. But if they're anything like mine, they'll probably be a hit-or-miss on quality, with the possibility of some slight modifications to the action if you want to shoot anything heavier than 300gr. loads. Mine shoots 260gr. loads with ease....anything heavier than that with Casull loads starts to jam slightly.
Depending on your front sight set-up, you may need to have it pinned in place, or get some JB Weld and try that. Mine came off years ago and I never had it put back on. I have some gunsmithing work that needs done on a couple of guns, and when I get around to it I'll take this down there to have the front sight pinned in place and have it cleaned and lubed as well.