If you carry a 4-lb carbon fiber tripod that caost $300 or more, it's sensible to look for a light weight but solid head, and this one fits the description perfectly. You give up some ease of use, because you have to rotate the ball within the head by 90 degress in order to flop it over to portratit (vertical) mode. (Acratech has newer model that appears to solve this problem.) But otherwise, it's highly serviceable and verygood for outdoor use.
With a moderately heavy dSLR (Canon 40D) and a medium tele lens, it drops very slighty after you tighten the ball. It's probably not suitable for a heavy (> 1000 grams/2.2 lbs) tele.