It's undeniable that flying a prop gets you the quickest upgrade and gives you some credibility in that you have good flying experience especially with no autopilot and GPS. However from what I saw the CAs at my previous airline weren't having any luck with the better majors/legacies out there citing not enough experience on jet/advanced airplanes. The only guys that made it to top tier airlines like CAL had a few thousand of pic and were instructors. I guess in the last few years there has been a rise in regional jet CAs applying though it has been tougher market for prop guys.