I've played guitar for well over fifteen years and gone through many different types of straps but I've finally found the one I'm most happy with - the DiMarzio Cliplock. Being a fan of Steve Vai I've seen these being used over the years but never tried one.
I went onto eBay and found someone in the UK selling them so I picked one up to give it a try on my PRS Custom 24.
It requires a screwdriver to fit but given you really want a locking mechanism anyway most strap locks would require you removing the existing buttons. The kit comes with all the screws and washers you need and I found on both a PRS and Ibanez the included screws fitted fine.
I will update as I start to use to use it more, loving it so far.