This could be an entire page of its own, but primary differences lie with user-friendliness. The ORX is much easier to use out of the box, has 4 preset search modes for Gold and Coins, and with the HP searchcoils, it offers three frequencies.
The Deus allows for much more user control over all settings, has 10 preset search modes and multiple customizable profiles, and Expert Menu, with the X35 searchcoil, it offers five frequencies. With the WS4 and WS5 headphones, you can also use the headphones as its own control box negating the use of the remote control for an ultra-lightweight and hassle-free platform.
Of course, there’s so much more that could be said, but these are the main points that sets them apart.