Installation is very easy. Plug in the provided AC Adapter, plug your mouse and keyboard into the front ports. Plug your monitor into the rear monitor port. There is an push button on the front that allows you to choose which system you are going to use along with red LED indicators letting you know which system is selected. One of the great things about the Omni Cube is that it provides signals to your other system that make them think that the mouse and keyboard are still connected.
All systems run great without any problems.
I think cheap, poor quality cables could cause problems. One thing to be aware of is that when you boot a machine hooked up to an Omni Cube, you should switch the Omni Cube to that machine's port, otherwise you'll run the risk of the mouse and keyboard not being detected, especially in Windows NT 4. I recommend the Belkin Omni Cube to anyone who is in a similar situation. Combined with the cables this setup will run about the same price as another monitor, but the fact that you can run four systems on a single monitor was a big money saver for me as well. I think you will be pleased with the results.