Specifically from the VP front: it's a total crapshoot.
I saw 3 people try for it my first tour.
One guy was rock-solid, on the fast track to IP and a #1 or 2 EP and he put in his packet just before he made PPC. He got picked up for helos and is loving life there, but he got totally spanked on his last FITREP because everyone "knew" he'd never be a skipper anyway after his transition.
One girl was, um, less-than-rock-solid and made it no secret that she "should have been a jet pilot." She applied @ 6 months before making PPC and was not accepted for transition. She also was not allowed to sign for a plane the last 4 months she was in the squadron, but that's another story.
The last guy was a rockstar. IP, Pilot Training, MC of an all-JO crew on deployment. He applied at the appropriate board which just happened to occur after he had been through FIUT. The jet community was willing to take him, but the VP community was unwilling to let him go because they "already had too much invested in him, what with IUT and all. Wouldn't he much rather go to VP-30?" Well, he WOULDN'T really, but that's where he