I have both. I carry my Dad's '94 on walk-about (for over 20 years now), killed my first moose with a Marlin 336, back in about '70.
Killed my first Dall ram with the Rem 700 .243, as did my wife on her first (only) moose.
Go with the .243.
Shot placement is almost everything - caliber and bullet weight matters, but recoil is less than the .30-30, promoting better placement. The 100 gr. .243 will do fine on most NA game with good placement. The .243 has less recoil, so will promote better placement. Louder, so use ear protection when practicing. In fact, double it up, plugs and muffs.
Bolt rifles tend to be more accurate than levers, tho my '94 is near as accurate (or better) as the 700 at 100 yards. Aperature sights vs scope, at that. MY eyes ain't that good anymore, and the 700 ain't that accurate, but there you go...
