Instructors don't like "ex FS" students because they allegedly spend the whole time looking at the instruments.
However, I think flight sim experience, particularly with FSX or other stuff which has pretty good scenery, is very useful, up to a point.
It won't teach you how to land, how to do stall recovery, etc. But it is damn useful in teaching navigation and general situational awareness. I used to fly my X/C flights on FS2000 before flying them for real the next day and found that very useful.
For instrument work, FS is fantastic. Never ever go airborne to fly any procedure if you cannot fly it on a sim. Going airborne is an almost total waste of (your) time and money if you haven't learnt what has to be done first.