Can't go wrong with either. I have both and I like the .58 better because the rifle is shorter and lighter. It is a Chamber's ESR and the stock design keeps the recoil very manageable but a heavy load like a 290gr round ball over 140gr of FFg will definitely get your attention.

“My horn is full and my pouch is stocked with ball and patch. There is a new, sharp flint in my lock and my rifle and I are ready. It is sighted true and my eyes can still aim.”
Kaywoodie