I bought a bunch of these for my small, but varied collection. I used them to hang an electric, a bass, an acoustic bass, a folk and a classical acoustic. They feel really solid, have a discreet look and the price is unbeatable. The stem is a nice medium length - the acoustics hang without their bodies brushing against the wall, yet the electric and bass guitars aren't too far away either.
I used them on drywall with metal anchor dowels. Screws weren't included, but I wouldn't have used them anyway. The fork is screwed into the mounting plate and can be taken off for ease of installation. Just make sure to check where the end of the fork thread is relative to the plate before mounting it to the wall, so the fork is oriented correctly when you screw it all the way into the plate. I made the mistake of mounting one of the plates without checking the thread and had to put a washer to make the fork tighten half a turn earlier. Without tightening the fork all the way in it felt a bit shakey. I guess that's a con, but I don't think it could be designed any better with such simple parts or for a similar price.
Recommended, would buy again.