AT THEIR BEST, i would vote for direct drive. The idea that they have "pulsing" etc... only applied to the earlier models and cheaper models, and is something that was promoted by their competitors (mostly British labels who didn't have the resources to compete against the Japanese technology, without resorting to half-lies and propaganda!). Later, high-end brushless, coreless ones with multiple Hall controllers or better, some with air bearings, are absolutely smooth and solid, with a torque that is higher than almost anything else. In terms of statistics, very little out there even comes close, and my ears seem to agree with the stats, in most cases.
Direct drives have been used for several decades for all commercial cutting lathes on which records are made, because they can maintain speed stability against the drag of the cutting blade... just as they can against needle drag. Only idler-wheel drives can compete, in this regard, and it audibly affects sound quality.
To get anywhere close to the same inertia and speed stability of a well-made DD, a belt drive needs a platter that weighs perhaps 50 pounds or more, and needs several minutes to achieve even close to the inertial rotational speed stability that a good DD achieves in less than one second. The size and weight requirements limits these models to the exotic/boutique range: the mass-produced Regas, even up to the Thorens (EXCEPT the Reference and Prestige models!) just don't quite equal the best DDs. The issue of elasticity of rubber belts, or vibration transfer of stiffer materials, is real. However, the BEST belt drives --the extreme ones with massive platters, etc... are probably the functional equal of direct drives, but on a value-for-money and availability basis, the DDs still rule.
Perhaps the most interesting ones are the idler wheel drives. They are rightfully known for their drive, pace, slam, etc... because the active "pushing" of the idler wheel overcomes the varying drag of the stylus against the vinyl, and creates a more lively and accurate sound than most belt drives are capable of. Again, only the huge-platter exotics have sufficient "flywheel momentum" not to suffer from this... and that is a major reason why decades-old tweaked-out Garrards can beat the best that VPI or Thorens can/do offer today. It's why both those brands decided to work on (re-)introducing idler-wheel models, after they had stopped making them.
You can't completely overcome the weakness of a belt drive, short of something special, on the level of a Walker Proscenium (which IS the equal or better of even the best "mass production" direct drives... but at that level, a Rockport Sirius III probably edges it out, and it is a DD!).
The trade-off with idler wheel drives is that it is difficult to get rid of motor noise with the motors they use, given the direct contact through the idler-wheel itself. Thorens tried a hybrid approach with an idler-wheel driven by a belt, but that just re-introduces a lot of the wow and flutter of a belt drive.
The best DD motors create a torque that is equal to that of an idler wheel, and which adjusts its force according to the drag presented against it, giving results at least as good as an idler wheel, but using electrical force in place of the physical wheel-contact force. However, these DD motors do not offer the motor noise found in the idler-wheel motors. That's why my overall vote goes to direct drive models. At the top end of the mass-produced models, they are superior. At the top end of the boutique models, I believe they also come out on top, due mainly to the Rockport Sirius mentioned already.
To be fair, ALL THREE types of drive can have OUTSTANDING sound, when done right/best ... and at the very top levels, it is difficult to decide between "different but equal" sounds. Some people like the slightly "warmer" sound of a belt drive: a tiny bit of distortion or "smearing" can sound comfortable, even thought it may be almost inaudibly small, and if that is what you are used to, suddenly hearing the greater detail and realism of a DD or idler-wheel can seem almost "harsh"... although much of the time, perhaps what is being heard is weaknesses either in the recording itself (mixing decisions), or in the rest of the system, normally not noticeable when the detail isn't as clear to begin with.
From the standpoint of theoretical engineering and physics, the better DDs should be superior... and in practice, they seem to be, too, at least at the levels of cost and availability that "mortals" can aspire to.
NOTE ONE: AT CHEAPER LEVELS, belt drives sound better, because it is much easier and cheaper to make a decent belt drive than a good direct drive. [Lots of people make great DIY belt drive TTs for themselves. When did you hear of someone making their own DIY direct drive?] If you can't find one of the better (later-era, Japan market) DDs, then a belt drive will probably sound better. If you haven't heard the best DD models, then you'll probably vote for a belt drive or idler-wheel.
NOTE TWO: I have heard Garrard 301 and 401 models in typical plinths, Lenco and EMT players, but have yet to hear the famed Shindo TTs. Perhaps one of those would change my mind and get me to move idler wheels above DDs?
NOTE THREE: Things like cartridges and styli, wires, and the rest of the system have an enormous impact on sound. In fact, the cartridge and tonearm, I believe, have a bigger impact on sound than the type of drive used to move the record. Also, there are issues of synergy: just as some carts and arms sound better together, so, too, do some cart-arm combinations sound better on certain turntables (or turntable types) than on others. Mats also can play a big role. All this makes it very difficult to truly say one type of TT is "better" or "best". In theory, I think the Rockport Sirius III --direct drive table with linear tracking arm, both tweaked out to the extreme extent of their technology-- is probably the closest thing ever produced to a "perfect" turntable. But if someone wants to give me a Walker Proscenium, or even a Shindo, instead, I sure won't complain! I like 'em ALL!
Sorry for another long post, but this issue is so complex, I don't think it is right to simply give an answer, without some justification and some discussion of all the compromises and offsetting factors that go into choosing one answer. The truth is, each different approach to spinning an LP has its strengths and its weaknesses.
