Oh yeah, the age old question argued for hundreds of years: which style is the better one?
None! Like most advanced martial artists know style isn't the determining factor. It helps to know a well developed style but it largely depends on how skilled your instructor is, how talented you are, how much do you practice, how much do you spar (or try your skills in a more realistic combat).
And to answer which form is more effective? Usually the higher the form the more effective it is. If you reach a third level form in mantis it is the same effective as a third level Wing Chun or other styles' form. There is no such thing as a style being the determining factor.
And with that, I was just browsing on the Karate styles and particularly interesting the Kyokushinkai Karate. These guys train for real and fight for real. They use no protective gear and fight full contact. The results? Check this out: click on the link below and scroll down to the third picture to see the recent Russian champion Sergey Denisow (note the site is in Dutch). I have respect for these guys cause they show what they know: http://www.kamakura.demon.nl/