Kassun,
The OS has better power to weight ratio. Here is a link to another option. http://www3.towerhobbies.com/cgi-bin...?&I=LXDXM3&P=0 A kid down at the field runs one of these in a 40 size Extra and it screams. He doesn't have an electric starter so its all chicken stick all day and he doesn't have any problems. He's been running it at least a year now and it hasn't blown up yet! For $79 I'm thinking about getting one myself!!