Rob,
There are many exhaust systems available for the C5/Z06 that offer different sounds, styles, prices and etc., and there are fans for every type made. Its easy to start a "flame war" on a forum by stating one is better than the other because the choice is subjective.
However, IMHO the x-pipe is fairly straight forward in its design and purpose (doesn't do much to produce sound and etc.). I read several surveys on both the Corvette Forum, Digital Corvettes and Z06vettes.com forums to determine which one is "best" before I made the decision to purchase the Magnaflow x-pipe .
Those that purchase the Corsa x-pipe usually do so when they purchase a Corsa exhaust system (which are excellent systems) thinking that the x-pipe is specially made to support Corsa exhausts, when in fact, any x-pipe works with any exhaust system.
Take a look at the x-link section of the three pipes and you will see a key difference (its slightly cheaper than the other two, however, I often find that price and quality go hand-in-hand). There are many opinions among many forums as to the quality of the Corsa vs. Magnaflow or Bassani that may be worth your time to read before making a purchase.
Mike