I have a D3V, which is the auto focus model. That means that once you have the image in focus, you can enlarge or reduce your image, and it will retain focus. This model has one internal condenser that is placed in one of three positions for working neagatives from 35mm-4x5.
I love mine, and I even use it as a light source for contact printing larger negs.
I will second Bruce in saying "Ask Harry" is the guy you want. He is a great resource for al your Omega questions.