Go with the 30-30, for the following reasons:

more effective, good deal more range with 30-30
no smoke - you can see which way the deer goes after the shot
no clean up req'd - this is an absolute MUST for muzzleloader, and a pain
no need to shoot 30-30 at end of day, or ponder how many days you want to carry that same load - moisture?
ammo is prob cheaper with 30-30, esp. if you're using pellets in ML/expensive bullets
follow-up shot possible with 30-30, for that deer you knock down and is regaining feet
30-30 is just plain classy!