The Spyderco Byrdrench is just like their old design, they just updated it a bit. In my experience the old style file was better (since it could sharpen the knife) and I never liked that it doesn't have needle nose pliers. It's kind of weirtd to use too.

The Buck X-tract doesn't have a saw or file and is only availible in a 1/2 serrated blade, which is what stopped me from picking one up. But, from what I've seen it isn't bad.

I haven't seen the Guppie yet, but not having a pair of true pliers would drive me nuts. Plus no file, saw, scissors, ect. It seems kind of gimmiky to me, but I'll need to play with one before I know for sure.