I'm a huge fan of Buck Assisted opening knives. I have a Rush which I love and a close friend owns a Tempest that while being a bit large for my tastes is a great knife. I also think the Sirius is a great knife as well. One of the things that makes Buck great for me is the outstanding ASAP mechanism they've come up with. I play with it all the time and it's outlasted the springs in every other assisted opener I have. I'm convinced that these springs just can't break. Plus I've taken the knife apart to examine the mechanism (shhhh, don't tell anyone) and as an engineering student I would like to add that I've found it to be first rate. Here's the thing. I've found the Ergos of the Tempest and the Sirius to be much more pleasing IN HAND than those of the Rush (which is the model I own and carry). I think that a shorter (Rush length) version of either of these models would make a much better addition to the line up than the Rush (or a short Sirius as a solid scaled counter part to the skeletonized Rush in the smaller sized knife market). So, anyone else out there like the size of the Rush but prefer the shape of the Tempest as I do?