I don’t care for strap locks that require replacing the strap pins on a guitar. And I’ve never actually seen any Grolsch bottle washers. What I have been happy with are the Planet Waves Planet Lock straps.
I recently got an Ernie Ball Polylock strap. Unlike the Planet Lock, it has no moving parts. But it does feel very secure. And it doesn’t feel quite as clunky as the Planet Locks.
Most importantly, though, I have one instrument—an Ibanez Mikro bass—that the Planet Locks won’t fit on. The Polylock does!