Re: Benefit to single humbucker guitars
I've heard the theory about the magnetic pull from the neck and/or middle pickups. I have no idea. Maybe science could help.
There's been one single-pickup guitar I've spent much time with, and it was pretty magical. It was an 80's Kramer Focus 1000, and it was awesome for a lot of reasons. It had this quality that I'll describe with a triumphantly vague adjective -- it was "on". I never fussed with the tuning like I've done with so many of my other guitars. It had a decked Floyd, Schaller tuners, and a really, really solid feel to the body, neck joint, neck, hardware, etc.
So it could have just been a really well-made guitar, which I believe is true regardless.