This was..horrible. The voices didn't fit at all. I noticed that Proffessor Namba is now Oak, and Richie is now Ash (I'm not 100% on this, but they sure sounded like it). May, like others have said, just sounded like a woman when she's ten (and had very little emotion in her voice), and Misty was a whole lot more breathy than Rachel Lillis' voice (she could barely scream anything). Brock was just.... like a 40 year old (which is funny, since Eric Stuart is also at that age and can sound successfully like a 17-year-old). James, of course, was the biggest dissapointment- he was trying to be...suave or something and failed and just sounded dumb. Jessie couldn't "yodel" (that's how Rachel Lillis has described her Jessie voice) and just sounded fake. Meowth was horrible- an even dirtier New Yorker.
The writing was also different- the characters said things they would mever say. Ash- "Mew's the BEST, Pikachu!" and Misty- "Oh pah-LEEESE! What-EVER!" and Jessie- "Oh, Rattata!"
And now begins my enthusiastic letter campaign...