The Zubak meter seems to be what all the oval guys use. At $279, it's pricey. I'm hoping that RC4LESS meter just lets me know when one is good or bad, I don't care about racing numbers. I'm not convinced the very most powerful rotor means a thing. I do think extremely weak rotors can be a problem, though.
http://www.hobbytalk.com/bbs1/showthread.php?t=187017