If you're going to get both, get the .30-30 in the Winchester, and the Marlin for the shorter rounds, especially if you're really interested in using it for action shooting. Marlin '94s don't need very much work to be competitive at the very highest levels of cowboy action shooting. Lots of guys do the work at their kitchen tables, using simple tools and basic instructions. This work isn't even really needed to compete at local level matches. Marlins rank up there with short stroked Winchester '73 and '66 replicas for sheer speed and reliability in action competition.
Many Winchester '94s fail to cycle reliably at high speeds with short pistol ammo. They are NOT popular for cowboy action shooting for that very reason. The many originals and reproductions of the Winchester 1892 are far more common in action shooting than the Winchester 1894.
Having taken Marlin '94s, Winchester '94s, and Winchester '92s apart, and actually gotten them back together, the Marlins are the easiest. The '92 follows, then the '94. With a decent set of instructions, the correct gunsmithing screwdrivers, and a couple of punches, the Winchesters aren't as bad as they're made out to be, just not as easy as a Marlin. I shoot real black powder in my rifles all the time, so I have lots of practice taking them apart.
If you wanted to muddy the waters by considering a '92 replica, check out this source:
www.stevesgunz.comYou can order guns direct from him, delivered to your ffl, already slicked up and very affordable.
In your shoes, my first purchase would be a Winchester '94 in .30-30, though. I've had a soft spot for them ever since I fired my great grandfather's '94 back when I was a kid. Winchester is offering them it takedown versions again, too.