It's a toss up and I'll let the folks who know their physics comment on the technical details. I believe belt is considered the more desirable feature of the two due to "isolation" of a belt helping to remove motor borne noise from being amplified. Belt drives are a little "fussier" and have to have belts changed and an eye kept of speed adjustments and such. Direct drives have qualities such as speed stability and ease of use. I have both and I prefer my Thorens 126 sonically over my JVC QLY5F. (But not a night and day difference) I believe both would be considered "mid range" turntables. The JVC is sweet as it has a tonearm that has servo's and it can track any record I own including the most warped in my collection. I use a Ortofon X5 high output moving coil on the Thorens and a Shure MK V on the JVC. I bought both new, The Thorens in 1979 and the JVC in 83. I still use and enjoy them. Both have been rock solid reliable and I would recommend either. You'll find that a cartridge makes a notable difference in sound. I have owned various Shures and Ortofons and wore out a Fidelity Research low output moving coil. The Fidelity Research was a beautiful cartridge and on the Thorens was wonderful. If your new to vinyl a Shure cartridge is a great place to start.
Have fun!
Have fun!