I've got both a 7x30 Waters and a 30-30, both are Super 14's. Generally, my 30-30 is more accurate with a wider range of bullets. As a matter of fact, I'll shoot my 30-30 against most folks that I know with a rifle out to 100 yards with a good rest, and usually win!
My 7-30 is a little pickier about powder and bullet weight. Could just be "luck of the draw" on the difference between the 2. It needs a little fiddling to get it to shoot the same.
If you handload and have the dies, either will do the trick. If you are seeking economy and all around usefullness, the the 30-30 is hard to beat.