There are many different techniques that are in the required curriculum of chiropractic colleges. Some techniques are gentler than others, while some take a great degree of skill to perform (Perfect practice makes perfect). Likewise, some techniques are more effective than others and the skill of the doctor of chiropractic plays a big role in the effectiveness of every adjustment. As far as "head rippers" go, I think you are talking about the diversified technique and variations of it. In Chiropractic College we learn that adjustments involving rotation of the cervical spine is bad for the IVD (disc), so I'm bothered that diversified is still taught in chiropractic colleges since it’s kind of heavy with the rotation.
Rotation of the cervical spine is not a proper cervical adjustment, and if this is what your chiropractor is doing than I highly suggest you find one with more skill. While even “bad chiropractic” is relatively safe, it’s in your best interest to see a chiropractor that is more specific with their adjustments.
I think I will post a thread on how to ensure you are seeing a highly skilled Doctor of Chiropractic and how to locate one.