Patrick, does it have to be a folder? If you carry it for work (and given your line of work), I assume you have at least a small tool belt or pouch, and if that's true, maybe you could even carry a small fixed blade with your other stuff. If that's an option, I'd look at the
ESEE 3, which you can get with a combo blade that you want, and includes a great sheath for about $90.
If you want to stick with a folder, I think in your price range Spyderco is a pretty good option:
* Para Military 2 (this will be pushing your $100 limit, but it can be found in this range, I just got one as a gift)
*
Manix 2 in 154cm (about $79)
*
Endura 4 (about $72)
Benchmade (2 good Axis lock choices):
* Griptilian (prob run about $105 for a plain black with combo edge)
* Presidio (same price)
Also, I have nothing against the Buck offerings and they are probably good, but I haven't owned any of the Vantage series and don't know much about them. I've read a FEW people giving reviews about QC issues, lack of centering, etc., but most seem to have good success if they contact Buck's customer service. You might want to try the search here on BF, search for "Buck Vantage issues" or "Buck Vantage problems", or similar strings, to get a feel for what recent owners have run into.