I'm with destroythealter, the A-F knives are some of the few Gerber's I like.
I've got all three now (just grabbed a Mini Covert a couple days ago).
My Combat (the full-size one) is a First Production Run model, and is a whole lotta knife! Mine locks up perfectly, but I've heard a lot of people complain that theirs aren't secure at all, so if you wanna pick one up, try to do so in person, so you can check the lock engagement. It's a big knife, and lacks a pocket clip (it comes with a nicely-made cordura belt pouch), so I don't carry mine around much. Opening it around sheeple just might cause a stampede!!
The Covert (the middle-size model) is easily my favorite. The blade size is just about perfect for EDC, although I wish it lacked the partial serrations. The handle is a thing of beauty: it's molded in three dimensions, with partial nested liners, so it feels like the slimmest knife I own. (It's isn't, actually, being of fairly typical thickness along the centerline; but the edges are so much thinner, you don't notice it.) Also, the Covert has a LAWKS-like secondary safety that automatically engages when you put your thumb on top in a saber grip. Disengageing it can be tricky when wearing gloves, or perhaps if you have very large thumbs. Oh, and the clip sits the knife down deep in the pocket, leaving very little showing.
The Mini Covert (the smallest model) seems pretty well made (especially for a Gerber!), but doesn't feel as good in my hand as my Covert; the edges aren't as slim and rounded. The clip sits it even deeper in the pocket than the Covert, and the blade on mine opens smoothly and locks up perfectly, but it also lacks the secondary safety of the Covert, too. And while it still looks very dagger-like, it's small size makes it more sheeple-friendly than the other two.