Mojo 40, with out a doubt, performs like a dream.
http://www.swanyshouse.com/index.aspx
I am sure others will agree. Any 46-55 size 2stroke or a Saito 82 also is a popular choice. Standard high torque servos will do the trick. Kit is super easy to build.
Mine is powered by a O.S. 55AX, perfect match, flight times with a 10oz tank are over 20 min. APC or Xoar 13-4 prop.