Basis table or SME

Is there much sonic difference between the vacuum and non-vacuum versions of the Basis?

Wrm57, yes and no :-)
No big difference when you own perfect, flat records
A real difference when you own warped records, a lot of Arms have real
problems to hold the VTF when moving up and down, you can hear that (when
the rest of the System is good for that).
Reissues with 200gr are pretty flat, unfortunately they don't sound as good as
their originals (generally), when you buy originals, then this vacuum version is
the way to go.
Another advantage from the vacuum Version is, the record does not "slide"
while playing (there is a resistance when the diamond is in the groove), a non
vac. version can be clamped, but with the vac. Version is simply all done right.

Syntax,
I bought last reissue exactly last year. Now any "new" records are only bought "used" and original or bad-to-worst early re-issues.
First dissapointment came from Classic Records re-issue of Tom Waits "Swordfishtrombones". The record and jacket looked pretty fancy, but onced placed on record sounded mediocre(politely speaking) compared to my original one. Than there were a few more. I guess all of them sooner or later will become cheaper than used ones

Thanks, Syntax. Another question: do you think a Minus-K or Vibraplane renders moot the benefits of the Basis suspension?

I think both the higher end Basis and SME tables are very good. I have only heard the Basis Debut Signature at my local dealer and the Inspiration at an audio show and the systems in which they were, sounded excellent, though I can't isolate what the tables were doing.

I do know a bit more about SME. I owned the SME Model 10 for nine years and recently bought the 30/12 with V-12 arm. Though I have not tried a Timeline on the 30/12 yet, it does show no variation with the KAB strobe and I heard absolutely no issues with speed. Isolation is excellent as is the build quality and service reputation of the company. Yes, as Syntax writes, the rubber bands look cheap, but I assure you they work very well. They hang from suspension towers in which are paddles damped in a silicone bath. These towers are certainly adjustable in height, so one can tune the suspension. They are very effective in both horizontal and vertical isolation. I think this is one difference between the Basis and SME suspension towers, though I know little about the Basis.

Another aspect critical to the SME design is the way in which energy is drained away from the cartridge. The platter is surface is a soft grooved material which mates very well with the LP. There is a screw down clamp and washer system. So this is passive but very effective at draining energy away from the stylus and in dealing with warps.

As Syntax wrote, Both tables tell you what is in the recording. There is very little detectable distortion from this system. Extension is tremendous, and backgrounds are silent. I would describe the system as a very effective platform for the cartridge to perform its best. Very little seems to be added to the overall sound from this turntable/arm system.

I did listen to my SME 9" V arm on the big table extensively before I switched to the 12" V-12 arm. The difference was pretty significant. Lower distortion, more extension, more information, great control. Based on the improved sonics of the longer arm, if you decide to go with an SME table, I would suggest the 20/12 over the newer 20/3. I have also read hear on Audiogon that the V-12 is superior to the 12" 312S, though I have not heard the latter.

I'm sure you will be happy with turntables from either of these great companies.