It what way were you disappointed in the servos you have been using?
Brand name high-end servos cost 100x or more compared to the cheap hobbycity varieties. (by the time you get to digital titanium gear ultra-torque hall-effect servos. http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXYPV1&P=7 )