Sota Sapphire with or without vacuum?

What is the sound difference between a Sota Sapphire with & without the vacuum pump?
I'm interested in some responses as well...
With the vacuum off, the highs are more pronounced, more "splashy", the bass is a little loose. I think this is due to the record being free to resonate due to the stylus/groove interaction.
With the vacuum on, things seem to be duller, but during careful listening you can hear details that were obscured before. There is more detail in hall echo reverberations
Your reaction may depend on downstream components too, cheap speakers (not to mention a cheap low resolution cartridge) may very well obscure the differences.
The effects are subtle but I think they're worth the upgrade. Certainly better than spending thousands on wire.
One thing that I have noticed is that the thicker the record the effects of the clamping seem to diminish.

Audio magazine did a great report on the vacuum option that was very enlightening. The reviewer commented on how much the "needle talk" was reduced when the vacuum was on.
I had a SOTA sapphire and upgraded to a Cosmos so I cannot give you an exact comparison.

I enjoyed my stock (series I) sapphire immensely. Decided to treat myself and bought a Cosmos and had SOTA make it a series IV. The Cosmos gives music a deeper blacker
background to spring from. The music opens up a little more and listening is more enjoyable. It is a "definite" improvement over the sapphire. Having said that, I could still live with a sapphire. I suspect that upgrading it with the vacuum would make the gap smaller between a sapphire and Cosmos.

Having owned both non-vac and vac. I highly recommend going the vacuum route.

Have Fun!
I've owned one Sapphire w/o vac, one w/ vac, and now have a new NOVA w/vac. To my ears vac produces greater detail throughout, especially with base tones. I've not noticed the dullness Dusty wrote of but agree about the enhanced detail and absence of resonance. For me the vac sounds nice and "black". Although I upgraded arm, cart,+ phono stage at each change I believe I can still say that I prefer the vac. I would not do otherwise at this point.
I agree with above, Ive owned the whole line and currently have a cosmos IV. Ive also owned tables with periphery rings. I prefer the vacuum to any other system. I have never noticed any "dullness" but I have noticed the highs are rich and clean in comparison to other tables.
By "dullness" I meant that the reduction in higher frequency resonances seems to make the highs less prominent when using the vacuum. A quick A/B would indicate that without vacuum you get more "highs" but that really isn't the case.
The vacuum is better.
I'm running a Star Sapphire w/ vacuum - I've never tried it without the vacuum, but in general it has very deep bass, lots of clarity and a very smooth top. It sounds great!
I had a Sapphire w/o vacuum years ago circa 1989, one of the first. It was an extrordinary TT.

In the mid-90's I heard a Vacuum model, and I couldn't believe my ears. It cost so much more and was NOT even close. I think it lost its resolution and detail, and sounded dull, not warm, but dull. I would stick with non-vacuum.
The sound is sweeter with the vacuum
Once you go vac, you'll never go back. :-)