Animation- good (as expected of a profilic Japanese studio on an American payroll)
Music- Generic and forgetable. May appeal to you, but I like something a little more contemporary like Kou Ohtani or Seikou Nagaoka.
Casting- Says Bang! Zoom, uses celebrity and cartoon voices in tandem. Nice. Haley Joel Osment as Takeshi, Michelle Rodriguez as Liz, Tom Kenny as Benjamin (the announcer who looks like a grown up version of Junichi [from the Raikou special] with Yoki's [Full Metal Alchemist] mustache).
The concept doesn't turn me on, since I've seen these kind of races before in games, Extreme G, Kinetica, F-Zero, Mario Kart...only with mecha, in 3 man teams. Add a dash of the International competition (children's anime/toy lines such as Bedaman, Yuugiou and Beyblade, series such as Daiundokai: Battle Athletess, Gundam and games like Street Fighter) and you have yourself what we should expect of US-funded anime: an ethnically diverse equal opportunity depiction of all characters, including countries that get screwed on anime distribution to boot.
Critical as I may be (mostly because I want to get in on the action, nothing about hate or anything. You know what jealousy is right?), I do hope that IGPX does open some doors for future US/Japan produced anime by would-be animators who can really use those resources (mostly webcomickers and Tokyopop "Rising Stars" entrants...as a last resort maybe Fred Perry or Adam Warren but only if we're really out of ideas, otherwise I'd discourage it). Who knows? Maybe my lifelong dream of TMS getting back into overseas animation will come true, or Toei can co-produce some major TMNT episodes...
I'll keep watching to see if it can amuse me.