Since posting in this thread (post #6) I just picked up another Griptilian. My other Grip is a BM custom from their web site builder thing that I bought in January (before they removed the Grip from the available models). It has G10 scales, a tanto half serrated blade, and is rock solid. The only way I can get vertical movement from the blade is if I pull back the lock, slowly unfold the blade, and slowly release the lock. This isn’t how I (or probably anyone) would actually open this knife, so I’m not counting this against Benchmade in any way.
The Griptilian I just got in the mail today has their plastic handles and the Sheepsfoot/spydie hole blade. This knife actually does have vertical movement even when flipped open properly. I noticed that if I grip the knife really tight after it is open, then there is no movement, but when I hold just the scales and try and move the blade, it moves up and down a little bit. I realized that there is no movement between the knife blade and the lock interface; it is actually the knife and liner unit moving ever so slightly within the plastic grip itself.
Long story short, I now see what other people are talking about, but this knife is perfect in every other way, so it’s a keeper. My G10 version is also perfect other than two of the screws in the grips slightly sticking past the inside of the liners (not interfering with the blade though). Anyway, I’m still a big fan of Benchmade’s designs and think you get a decent value with some of their off the shelf models.