The belt drive versus direct drive discussion can get heated, but both can be very good. Implementation is probably more important than type.
DDs tend to be less maintenance intensive until the electronics go, at which point they become significantly more complicated to deal with, whereas most belt drives just need the occasional part. Plastic box turntables of all sorts tend to be susceptible to feedback (not just gross howling, but a fuzziness from less obvious resonation), but the same could be said of the sprung top belt drives unless they have the advantage of substantial mass, which the Sansui might. The only way to tell if either table suffers from lack of isolation is to listen to both of them.
One possible factor is the type of cartridge you want to use, and, possibly, what sort of frequency balance you like. The Marantz has a lowish mass arm, whereas the Sansui has a higher mass arm. If you like high compliance cartridges, the Marantz arm is probably better, but if you like low compliance models, the Sansui will suit better. And often, more mass can result in weighty bass - of course it can be too weighty and sound leaden.
I disagree with Thunderbox's apparently sensible comment that looks don't matter if you listen to, not look at, your turntable. Turntables are more interactive than most other components, and looks and feel have a lot to do with how you feel about a table. Among other things, you probably can't use that table without looking at it. There are plenty of tables that sound fine that I can't stand the looks of, or how they feel or work, and won't have in the house. Tastes differ, but you almost certainly have feelings one way or the other - listen to those feelings.
