Direct Drive vs. Idler Drive vs. Belt drive

I'd like to know your thoughts on the strengths and weaknesses of each drive system. I can see that direct drive is more in vogue over the last few years but is it superior to the other drive systems? I've had first-hand experiences with two out of the three drive systems but looking to learn more.
21192e21 5d00 4ded bea1 72869e5cf35dscar972
Own 2 technics SL-1200mk2’s

best TT ever built!

And this is only an entry level into SL1200 series, i also have a pair of Sl1210 mkII for more than 20 years, fully upgraded in the last 7 years, not in the main system, but it was my first adult turntable :) 

The next level for me was this SP-10 mkII in teak wood plinth with Reed 3p tonearm and Glanz 61 MF cartridge. 

And not so long ago Technics returned with new turntables, different models with prices from $899 to $4000 in SL1200 series

I just don't understand why people are so brainwashed with those rega and related belt drives. 

Regarding air bearings I am wondering that many friends around here mix air floating devices with a real air bearing design. Even Mike Fremer mentions air bearings with an air floating deck.
To my knowledge only two designs (in the world) are running on air bearings. May I have overseen a development?
I found Herb Reichert's piece in the latest edition of S'Phile uhhh....interesting. He reviewed the J.Sikora Initial which is belt drive and in an apparent effort to heap his usual unfettered Primaluna type hyperbolic and unrealistic praise upon it, he took a jab at his own Thorens TD124 calling it (I am not home to quote verbatim) a bucket of nuts and bolts by comparison. All this using a Jelco arm while the photo S'Phile published with his review shows a Kuzma, go figure. I wish I had his phone number so I could tell him that I will take it-his TD124- off his hands since he finds it to be junk. 
I bring it up here because I happen to believe that all three can be very good. It all depends upon implementation. Herb is a gifted writer but unlike Art Dudley who many have lumped him with, he has very mediocre gear and an apparent low bar used as a reference. 
For Herb Reichert to call the Thorens TD124 a bucket of bolts is like some proud new Tesla owner declaring an original mint Shelby Mustang to be outdated trash. Fine. That does not make it so and 98% of automotive cognoscenti would take the Shelby seven days a week and Sunday too. 
Yes, I have a TD124. Highly modified. And a highly modded Garrard 301. I suspect Herb's TD124 has not be properly cleaned, serviced, or modded and that he has an even worse arm than a Jelco (not bad mind you, but Jelco is not close to the top either) mounted to it. Herb, Herb, Herb, stop smoking so much herb Herb. 
@thuchan , the need for an all air design became obvious when I attended a manufacturer’s rollout for the big new Technics. They had a naked motor available for admiration, and so I picked it up, put it next to my ear, and I could hear the sleeve bearings when I twisted the spindle. Not loud, obviously, but the noise was there if you listened carefully. My New Way amorphous carbon thrust bushing is dead silent!

Did you install that air bearing on the main platter bearing?  Is the motor that drives your set up similarly equipped with an air bearing?