1. Graphics.
LttP had advanced sprites, OoT had early polygon models. Sprites haven't made serious advances since then. Polygon models, however, have. By now, we're used to far better looking graphics, and the blocky figures from Super Mario 64, Ocarina of Time and Final Fantasy VII, while nice at the time, are looking atrociously bad. Just one example: The Great Fairies.
Winner: LttP
2. Atmosphere. A Link to the Past had a colorful, beautiful Hyrule. Yes, there were monsters running around, but still, everything looked cute. There were the sequences in the Dark World, but there weren't too many of those, and by contrast, the "Light World" looked even more beautiful. In Ocarina of Time, the "child" Hyrule already looked kinda bleak. A huge part of this is owed to the graphics again, since back then, they couldn't use more polygons or better textures. So we've got Hyrule Field, a bleak area full of peahats (and, at night, stalfos). We've got death mountain, the empty Zora caverns, Jabu-Jabu's belly... and then we go seven years into the future, and everything's gotten even worse.
Winner: LttP
3. Characters.
Everyone in both games has their own story. The kid with the bug-catching net, the flutist and his grandfather, the soccer player and his ball, Link's uncle and Blind are on LttP's side, whereas OoT has the sages, Fado, Dampé, Guru-Guru, Grog and Bongo-Bongo.
Tie.
4. Overall storylines
It's basically identical. A little boy gets three medallions, then the master sword, then travels to the Dark World/the future, where he has to meet/rescue seven characters, then has to defeat Ganon. But Ocarina of Time has more twists.
Winner: Ocarina.
Overall verdict: LttP wins.