I tried it for acute pain when I tore my piriformis. That was some of the worst pain ever, in a close tie with sciatica. After the first session, I felt some relief of pain. The pain was caused mostly by muscle spasm, so I believe the needles calmed the muscles down temporarily. I went back for a second treatment, and the practitioner wanted to do something called "cupping" (which undoubtedly was an upcharge). Well, "cupping" didn't go so well; I left that session in more pain than before.
I would not choose acupuncture for chronic pain either, myself. Maybe acupuncture will break up some trigger points, but I feel that most chronic issues usually need active treatments like mobility and soft tissue work and correcting imbalances.