Not really any advantage unless you want big arm muscles and are too cheap to buy a gym membership. Driving a manual rack in stop & go traffic or doing a lot of parking is very tiresome.
1) About 30 lbs. less weight.
2) Adds HP by not spinning the power steering pump.
3) No leaking fluids.
4) No whining power steering pump.
5) Cleans up the engine bay.
6) Car goes faster.
Hmm, I just answered this yesterday (I'm losin it).
If you are doing this because of the feel of the stock steering, an interesting possibility would be using a 94-95 rack instead. I DONT know that this will work, though a member here has posted that it does. The steering feel in my 94 is awesome compared to the 88 GT Vert.
Just an option to research, depending upon your reason for removal.
One other thing - if swapping to manual steering I might worry about the column getting loosey goosey (those torx fasteners have a propensity to work loose even with PS).