I bought the nitrofire this year and love it, the firesticks make it super simple, no breech plug, just break it open and remove the firestick to unload. No big plume of smoke when you shoot it either.
My experience leans toward 50 cal. for supply convenience and inlines have dominated the market of late. Traditionalist of course prefer sidelock or flint.
I suppose you've figured it out by now, just updating an old thread
I got into it 2 seasons ago. Ive got a. 50 Inline CVA a Hawken in .54 and go figure the only one I've killed a deer with so far.. my repro Enfield 1853. Backyard doe. Those .68cal Minie balls sure blow holes in does.