No contest. Belt drive is light years better in terms of sonics; lower noise floor, cleaner signal, etc. Motor isolation is critical because of cartridge sensitivity.
DD turntables were built because they were cheaper to make at a low price point and owners didn't have to mess with belt replacement. Now that there is no mass market demand for turntables, there aren't too many DD models to choose from. Most of us who still have turntables or those who are in the market for turntables are looking for an improvement over digital, hence most, if not all, "audiophile" turntables are belt driven.
Of course, for DJ use DD is the way to go because one could simply hold the platter (or move it back and forth) for easy cueing and sound effects.