I personally don't like Hot Stix, but that's just me.
there is so much that goes into a fitting it's too much to explain. It's a combination of science, art, and guesswork (based on previous fitting). Just a simple list:
1) Swing speed
2) Angle of attack
3) where you load the shaft
4) spin you put on the ball
5) what your tendecy is towards clubface orientation through the ball
6) tempo
7) ball that you play
8) How often you go "all out" on the driver versus just a "normal" pass at it
9) What shot shape you play (relates to some above)
10) Swing plane (relates to some above)
there's a simple 10 part list. now a good fitter probably go through all of these with you but they are going to definately be thinking about them.
Here's my opinion on how to find a good fitter:
1) Search the net for reviews in your area, post/search questions in various golf forums around the net. good fitters are like good local diamond sellers, not promoted much and known more by word of mouth.
2) Try to find someone with a trackman, if you can't look towards a Zelocity or a Vector equipped fitter
3) Save up some cash and bring the REAL BALLS THAT YOU PLAY. Now i'll admit this will add to the cost of the fitting but most range balls suck. They are severly limited in ball speed and sometimes spin too little or too much depending on what kind the range uses and/or how worn they are. Your results might be vastly different between a range ball and a real ball. These days you can get Pro V1s and/or callaway "practice balls" or even "x-outs" for much cheaper.
4) If possible try to get someone who has the ability to quick change clubs, there are various companies that produce this.
5) See if they have varied clubheads and face angles you can try
6) See if they have actually MEASURED the loft/face angle of the head you are using so that you can order that EXACT same head (at least for loft) then you can bend the head open/closed if needed.
Sorry for the long response but there is a lot that goes into it, also a really good fitter can even get pretty darn close by just watching your ball flight and swing and possible make setup changes to alter your driver ball flight. sometimes getting "fit" isn't the answer, it's learning how to hit the driver properly BUT on the other hand if you are set in your ways and don't want to change you can always get the equiptment to make up for your flaws.
Hope that helps