I'm the advocate for ISIS. I am using the free version of ISIS Draw 2.5, and the installation works fine with Crossover 3.0.1. The program will not start until after you move the mdlctl.dll as described in Tips & Tricks. As far as I can tell, all drawing operations work. Sometimes the cursor jumps around while you try to draw so your structure will look strange. Saving the sketches works fine. When you exit you get a "fatal error" message rather than a clean exit, but it doesn't seem to hurt.