I have got a CST model 1550. That's an optomechanical unit, with the same form factor as the L-Trac. It is not super high res, but it works well with mild or even zero software accel.
I HATE the form factor on the CSTs. That's why it's for sale. $30 shipped to CONUS.
The wedge-shaped CST angles your wrist unnaturally upward. IMO it's not comfortable. It would be better if you could couple it with a palm rest, but the thin end of the wedge blocks a palm rest.