TT mats

I have a VPI Prime Signature. I could not stand the "hard" sound from the bare platter. I got the 3mm Achromat, I use the peripheral ring and the sound sweetened up and became more musical. VPI claims the paper shipped on the platter is supposed to be used as a mat also. I don't know what they listen to, but I want musical music. I had heard about the Achromat on many forum threads, but Michael Fremer's review was what sold me.

right now I am using the Boston Audio Mat with the Stillpoints LPI.  Tried the Achromat and was not impressed initially.  will revisit

Micro Seiki CU-500 is hard to beat.
SAEC SS-300 has the best price on the used market.
Took those pictures long time ago, but still use the mats and don;t want to change them for anything else. 

@chakster Both of those mats are metal placed on a metal platter. That’s like placing a record directly on the brass top plate on the new 1200G.

There’s not much dampening going on there.

Can you describe the sound difference between what you use and a mat made out of elastomer type of material?

To get back to the OP, I think your best bet if you can afford it is to try a number of different mats and find the one that works best for you. The various threads on this topic seem to demonstrate that people have different results with different mats according to the particular character of their system and its problems (i.e. the sources of disruptive vibrations or tonal inaccuracy). That makes it hard to generalize. 

That said my turntable is somewhat similar to yours (as is Stringreen's) so maybe my experience will help. The TT is a VPI Aries 1 with Classic Platter and a Teres Audio rim drive motor, among other 'mods'. I've tried the VPI rubber mat (overdamped and dull), Herbie's Way Excellent TT Mat (Way too trebly and harsh), Auditorium 23 mat (nice but a bit too polite), the new Oracle acrylic mat that supersedes the old Groove Isolator (also nice but a bit too glassy and well, acrylic-sounding), and no mat at all (also a bit 'juiced' in the upper registers).

In the end I settled on the Funk Firm Achromat. I like the theory behind it, and I found that sonically this mat far outweighs the other TT mats on my 'table. It sounds to me like it's doing what it claims. I use it with a VPI peripheral ring clamp, which seems to me to accentuate the impact of whatever surface the LP is resting on. I also just added a Stillpoints LPI after a period using the VPI center weight, and I find it to be a significant upgrade. I expected that to be the case because of the rim drive - it has to be adding vibrations to the platter, no matter how smooth the motor is. But I'd guess your experience would be somewhat different if you're using the standard VPI motor and belt.