Ok guys

Put me in the no dust cover camp, that's +5 and counting. Enjoy the music

A dust cover is a no-brainer to be desired. Nobody wants dust on their records, turntable, tone arm. Nobody wants the acoustic energy in the room vibrating the sensitive cartridge/arm system. The trick is to do it in a way that doesn’t create more problems than it solves.

i guess dust covers are like politics, religion, olives, and Kenny G. All taboo subjects in polite company.

It’s interesting that the pro dust cover guys, so far, are both owners of SOTA turntables. I owned a Star Sapphire Series III with vacuum  for most of the 1990s, and never used the dust cover. Al is correct that the felt platter mat does/did accumulate dust.

Mc,  https://www.sleevecityusa.com/Antistatic-Record-Cleaning-Arm-p/tac-01.htm. If you get one let me know there are a few tricks to setting it up right. 
Guys, as I said before the SOTA sounds better with its dust cover on and down as does the SME. It is like taking the blur out of a photograph. I have done the fore mentioned experiment and I can routine tell when the dust cover is down blind folded. If your turntable sounds worse with the dust cover down then have a platform dust cover made or get a new turntable. Not using a dust cover is not an option. Record safety is paramount. Using a conductive sweep arm will help but still incidental dust will fall on the record not to mention get into your tonearm and bearing.  

Lewm, I also own an SME and it benefits also as does the Linn LP 12
All suspended turntables. I suspect the Air Force 1, 2 and 3 will also benefit. My opinion is based on suspended turntables. They are the only type of table I have ever own except for my very first one (TD 124). I would never own anything else even though my equipment cabinet rests on concrete. The SOTA is a brilliant turntable for the money. It easily runs with the SME, a table that costs 4 times as much! The only down side is that it does not take a 12 inch arm and some arms like the Tri Planar will not fit. I also must warn that Putting a 4 Point 9 on the newest version of the Cosmos is apparently difficult. An A goner ordered one with a 4 Point based on my opinion and SOTA is having a hard time getting it to fit. I think they will shoe horn it in but just barely. SME's and Origin Live arms fit perfectly. Unfortunately, SME arms are going to get hard to find because the company will only sell them with their tables, a stupid decision IMHO. SOTA is thinking about making it's own arm. Lets cheer them on!