Steve- The OL is much quieter, giving the table a blacker background. Check out the thread "A Simple Test" to hear how much noise is being introduced by your motor. If it is what mine was with the WT motor, you might want to consider the OL as motor noise in it is nearly non-existent.
Dynamics are also considerably improved. Don't know if it's due soley to the lower noise floor or if it's more to do with better speed stability or a combination of the two, but it's a very nice improvement.
As far as the OL power supply upgrade, I decided against it as I figured that it wasn't the biggest bang for the buck. Plus I have a dedicated AC circuit with it's own ground and an AC conditioner that cleans up the power pretty well so the basic power supply can do it's job efficiently. Even without the extra 120VAC treatments, you're getting almost all the way there with the DC motor and basic power supply. Jay at Audio Revelations will let you upgrade the basic power supply to the premium one with a full credit in 30 days, so you can try the basic and move up if you feel the need. Heck, he might even loan you the upgrade if he has an extra one kicking around and let you decide.