Hi, I have an Acratech ball head for about a year now. I do admit that it runs a bit high, however its design, build quality, construction, materials and operation are absolutely flawless and nothing but superb. Its a novel ball head design that is open (easily cleaned), light weight, holds 25#, is a ball head, gimbal and also you can invert any of them to create a panning ball head. Give Acratech a call and their technical support is wonderful - the president, designer, chief engineer and master machinist - all go by the name of Scott. No question is too trivial...
Acratech, Inc*::*Ballheads & Tripod Accessories
Now, I did get a Kirk L bracket for my K20. It fits my K20 quite well and is well made. It was more specialized than Acratech's universal L bracket. Both Kirk, Acratech and RRS use the Acra Swiss mounting, so they all interchangeable and work well together.
hope that helps....