I've become very picky regarding liner locks. Even many (lower-end) frame locks. I was scared off from buying a Kershaw Vapor (the smaller version) because 2 of them that I examined at Wal-Mart closed with a simple push to the back of the blade, like you would close a slip-joint SAK. The blade promptly closed with hardly any resistance at all.
The most secure liner locks I own are a 440V Spyderco Military; 2 Benchmade Strykers; an old AFCK; and a few Kershaw Liner Action folders. I have an Al Mar SERE 2000 that I thought was perfect until something about the detent became odd, and though it still locks up fine, it won't close properly or stay closed. I suppose I could send the 2K in, but I haven't gotten around to it.
Jim