Ok, so once I got my layout set up, I tried running w/ 18 tables on FTP. System performance was meh:
Screen tearing while stats load on various tables
High CPU usage
For reference, HM doesn't do a lot better in this category (depends on how many panels I use). PA HUD is quite usable and doesn't drain my resources as much as any of the next-gen HUDs at this time. Haven't tried w/ PT3 since its HUD doesn't support color ranges yet.
FTP seemed to run okay even if the rest of my system was super slow, though.
The only other problem I noticed was that when running a ton of tables, stats were very slow to update (whereas w/ 1 table open, they update very fast). Like, a 6-handed table got down to 3-handed, and it took at least a few minutes before the stats disappeared over the empty seats. PA HUD generally handles this within just a couple hands.
Possible bug: When stats were loading on my tables and most tables in the list said "NaN" for vpip/pfr, I unchecked the box next to one of them to disable stats and then rechecked it. Stats appeared on the table, but all of them just said "..". Even after stats loaded for all my other tables, this table would not load them (even after unchecking and rechecking the checkmark).
I might try playing w/ it later, early impressions though are that performance could use some improvement. fwiw my system is 2.4 GHz C2D, 2GB RAM.