There is more learning to black powder than modern cartridge rifles. To be proficient with a muzzle loader you have to spend the time. It is a mater of learning how to make it go off each time and that takes time and practice. That is usually 2 things folks don't want to put in. Your hunting skills also have to change. That takes time as well.
Personally I use percussion rifles with patched round ball. I was fortunate to have good teachers when I took up muzzle loaders.
In my opinion, unless you are willing to put in the time and effort with muzzle loaders, I'd say stick with cartridge rifles. YMMV.