I've been seeing a chiropractor for 30 years and have always felt better after a treatment and never worse. Many people love to say how much they hate Chiropractors, how they are quacks etc., etc. but many of them either haven't tried it or have gone only for one or two treatments with expectations of instant relief.
Over the years when my chiropractor has been away, I have seen other chiropractors in his absence and can tell you that they aren't all created equal...which is true with every profession. Look for someone who puts your health above all else.
The reason why chiropractic will always be around and have loyal patients is because it works...that simple.