I've used them from time to time since one of my dear friends is a chiro. I think much of is is quack practices (especially NAET and such) but I know my husband (who is extremely physically active and in great shape) gets some temporary knee relief when his knee starts acting up. When I went with tingly/numb fingers that wouldn't go away she fixed it within 10 minutes. I left feeling better and the problem didn't return. But I wouldn't go for just anything.
I have another friend who left his chiro practice and went back to college after deciding it was all false. My friend who is an active chiro, well I love her to bits and she really really believes in what she does. I don't think she intentionally misguides for profit.
I really do not believe in much that doesn't have science around it, and things like the laser that affects you on a "cellular level" simply don't have science behind them. I really think Chiropractors need to start working more in the science behind what they do and contributing to the medical community if they want to be taken seriously.
We're at a time now with technology that Neurophysiologists do have methods of recording the passage of impulses in nerves. They can actually read and understand the nerve impulses in a body, but as of yet there are no definitive studies on how the "subluxations" affect the nerves. The amplitude? the wave pattern? The frequency? Yes they are interconnected, but how really do they relate and to what degree?
I just think we're at a point in technology that these claims need to be backed up with solid data. We should be able to hook someone up, see the nerve interference- adjust them- and see the interference removed if chiropractic is going to be taken to the next level and be accepted as a factual science. We have the technology for this... so it is time we used it or acknowledged that we don't really understand chiropractic. And chiropractors haven't been able to detail how it works in a scientifically accepted way... that highly discredits them to me.