Micro Seiki, or TW AC-1

Another good option is a Basis Turntable. Very good technical solutions, the
Designer really has knowledge about turntable Design. Some can be upgraded
and even when you compare his belts to others, you realize, he is miles ahead
from all others. Precise Motor, uncolored Sound, excellent dynamics. In a way a
'tool' when you want to know what's really done with the records in the
Recording process. Design done right.

Oh the tap test. I worked hard to modify my turntable ( nude JVC TT101) and the supporting shelf so that it passed the tap test. So clearly I believe it is somewhat important. And yes I do believe the sound improved in terms of clarity and precision, especially at crescendos. When I mentioned this in a thread on the new NVS TT, I was widely booed. So many people think it unimportant - but have they ever heard the difference it makes?

I do own a Raven AC 2 since 2007. Did six modifications on it so far. Can't imagine to hear it in it's stock state again.
I use the battery driven motor controller as well. But i can't say whether it has speed stability or not - because i can't set up the right speed at all.
As measuring tools there a stroboscope disc with 300 Hz flash and a Timeline. Viewing the stroboscope disc for detecting the rotational behavior of the platter is like watching the clouds. For me, the Timeline is the way to go. And what is this device revealing on the Raven? Maybe you could hit the 33,3 speed mark, pushing the up and down buttons of the controller, when using the stock belt. Given a specific belt tension, too.
I'm using string or tape - for the reason of better performance. Doing so it is not possible to set up the right speed (33,3 or 45). The Timeline shows this fact undeniable: the platter always rotates to fast or to slow. The Laser never stands still on the wall. Pushing the buttons does not help. Why?
Its because of the regulation build in the motor controller. It works with incremental steps of speed regulation. Tiny steps, but STEPS. If you need a value between two possible steps for perfect speed adjustment, and this is the case with string or tape that have different diameters, - you are lost with this kind of construction.
So the Laser is wandering on the wall - i'm not able to say if it does it with regular speed.
For future improvements (or turntables) i never would accept such as a drive management again. Only a ANALOGUE solution with a classic potentiometer providing all values necessary.
I think this issue is basic. Not only to the Raven.

Regarding Timeline, I agree that the step on TW motor control is a bit too big. VPI SDS give a smaller increment in speed adjustment. With TW, it was always either a little too fast or too slow. However, I use my TW without any center weight. I setup the speed with a record on the table and cartridge playing the record and usually just choose the speed that is just a little bit slower than what it should be. I assume that when I take Timeline off, the platter would spin a little faster with less weight. So I imagine that using Timeline, I would never really hit 33.3 or 45 exactly anyhow. On the other hand, once speed is set, I have not really notice significant drift in speed that I can detect with my eyes using Timeline.

People! I will tell you don't buy a Timeline and find out your tables are slow or fast, it will drive you nuts! Once you hear a table that has PERFECT speed control you will then understand what all the fuss is about. I had a TTWeights table and thought it sounded great until I tested it with a Timeline and found it could not keep the correctly speed. I searched and searched and once I found something (and it's irrelevant what I got) I then understood what I was missing. So I repeat, don't buy a Timeline unless you want to start all over again, enjoy what you have.

(Dealer disclaimer)