Bob F.
Yes, currently it only accepts Waves Plugins, however, Waves is working on an update to make it able to accept other plugins. I just downloaded and install the software through Waves Central. I created a separate folder called Waves Studio Rack so that I could find it faster w/o having to hunt through all of my Waves Plugins.
When I inserted it first on keyboard track, it took a few seconds to come up. The GUI lookes really nice. adding plugins was really quick and they were already organized in groups, ( EQ, Dynamics, Delay....) really nice.
The Plugin is really easy to use and it doesn't take up additional processioning power to have the Studio Rack in the session.
I have some more probing to do, butt I like it very much.