I think, as a player, you should find what YOU think makes YOU perform the best. It is YOU shooting, NOT the sponsor. If you shoot WELL ENOUGH with your cue, then the cue maker (or shaft maker) will probably find YOU.
If you shoot with whatever a sponsor decides you should use, it may not be what is best for your game (mentally and physically). Earl could shoot lights out with his Cuetec, but he hated it and claimed it ruined his game. I don't necessarily believe that, but the money must have been good enough to make him "like it a bit".
If the sponsor is giving you sufficient money to endorse them is one thing, but t-shirts and a cue, once in a while, wouldn't be enough to sway me. I can use a cue for years and years and only need tips.
As far as hit and feel, I have a Predator 314-2 FAT shaft that I switch back and forth between my Titlist conversion and my ADAM Japan cue. Both cues are very close in weight and balance and the only difference is the Titlist is full-splice and the ADAM is not. The cues play similarly but you can tell the difference in feel and hit.