The button lock is a very sturdy lock style that doesn't get much press. It's been used almost exclusively for auto knives. I've handled several WH button locks, and I am confident in their ability to take and handle much use and abuse. I own a Protech Runt with a button lock, and it's been around for about 7 years, and no signs of failure, or slippage. I think the main reason you don't see more of them is because they are a bit more expensive to do correctly. Most auto enthusiasts will agree that it is one of the stronger locks available. I don't think you could go wrong with a company like William Henry.
Daniel