Part 91 is a tough sell from the hiring perspective. You are hiring a virtual unknown. When you pay to get your check rides from FS and have one supervisor and a couple of coworkers, sometimes the end result may he someone who may have slipped through the cracks.
There are many here hired with part 91 time, but only a few with ONLY part 91 time (there was one in my class, but he was very well connected at swa. I spoke to a background checker at length about this and he said it is very tough to get a read on corporate guys.