I had a Speck Fitted on with a SGP Oleophobic without much issue. I did eventually crack the Speck Fitted, though, taking it on and off. I emailed Speck for a warranty replacement. They sent me a different case as a replacement, but stated that:
"That case doesn't work with screen protectors"
I asked if any of their cases work with screen protectors and they said:
"None of our cases come with screen protectors and will not work with aftermarket ones"