Hi Pedro,
I'm very happy with my Nixon. It is the second one that I've had. The one I originally received did have a problem. It would not hold its setting when lowered. I called Manitou and spoke to the sales director. The service I got was very good. He personally checked out the replacement before sending it with UPS. The replacement has been faultless. I think that they had a production problem for a while.
It can be supple or not. It is a SPV fork and dependig on the SPV pressure it looses some small bump absorbtion. I run it quite low at 50 to 60 psi. and I can stand up and pedal with very little motion. If you don't like SPV, I think the Nixon Super is the same fork except with TPC damping.
The IT works very well. I've put the control on the left side of my bar as I tend to use the rear changer more than the front but you can fit it to either side. Push the control and as long as there is weight on the fork it compresses. You can release it anywhere between a minimum of 40mm travel to full travel of 140mm. I've measured it. It bottoms out against the rubber bottom out bumpers. There is no change in the spring rate at any travel setting. Extending is not quite as easy, unless you'r good at doing wheelies.

Unfortunately I'm not but I'm practicing. You need to hold it up a second or two while holding the control and it extends.
I have had no problems with mine changing the travel setting on its own. I set it where it feels good and thats where it stays.
If you are asking is the IT control sturdy, yes it is well made. The actuator is solid brass and won't break easily and I'm sure they are quite cheap to replace. The cable housing is ordinary brake cable.
Hope this helps,
Ronnie.