I had an excellent thread about this very same issues about two weeks ago --before the servers crashed! I was pondering the switch myself but have decided to stay power.
I'm going to ask you all the questions they asked me.
Why do you want to switch?
Is the car a daily driver?
What type of mustang (i.e., year)?
Are you having any issues with the steering now? If so, what?
1966 w/289
somewhat Daily driver/ project
I need to replace the cylinder ram as the boot was almost gone when I got the car.
The alignment shop says I need to replace the control valve
Aslo what would indicate the need to replace the control valve?
I converted my power to manual. I bought a manual steering box from ebay for $125. Had to remove my header on the drivers side to change out box. You need the pittman arm as well if you get the box. Manual is fine, a little tough while not moving. If my power steering had already not been robbed prior to getting the car I would have kept power. You can easily replace the boot on the cylinder. Why did they say you need a new valve? Do you have excessive play? If not and the valve isn't leaking I would just install a new boot and keep what I have.
None of the power steering components seem to be leaking, as far as play is concerned, this is my first mustang so I don't know how much play it should have. The front end is out of whack so I am doing a suspension & steering linkage rebuild with a kit then getting it aligned. I should know if the steering system needs help after that.