In my conversation with the 2 companies serving as US distributors of Acoustic Solid and Acoustic Signature 'tables, I got a different story. I'm told that A-Solid has manufactured their tables in-house for about 10 years. A-Sig started a few years back when the director of sales for A-Solid set up his own shop to manufacture tables (in-house) from the A-Solid designs and sell them as A-Sig. Some changes were made (dry bearing), but the tables are very similar and both are reportedly very good performers. FWIW, I recently ordered an A-Solid "Solid Black" table w/arm & cartridge for a second system. It appears to represent good value, but I'll know more once I receive it.
I think the bottom line is: Both companies offer very good tables because the common underlying design is very good and execution by both companies is well regarded,
Good Luck.