I have only used traditional blackpowder and I only have BP handguns, one .36 cal revolver, two .36 cal pistols and a .45 cal pistol. They are fun to shoot but I don't really enjoy the loading process and I really don't like the clean up.
I do have a Wesson & Harrington Buffalo Classic in .45-70 that I loaded up some black powder cartridges... lots of smoke, kind of fun but I went back to smokeless.
Black powder cartridge in a breech loader seems to be way more fun than reloading a muzzleloader, at least to me.