I loved Ender's Game and Speaker for the Dead. I was torn through both, the second in three days, which is pretty much unheard-of for me. However, Xenocide has been disappointing so far.
My hypothesis is that Orson Scott Card wasn't meant to write 600+ page books. Under 400 seems to be his sweet spot. His prose is too dense when strung out as far as it is in Xenocide.
The new characters in Xenocide are well-written, although they're a bit of an oddity amid the others. I can deal with English and Portugese speaking people together in one book, but throwing Chinese in as well makes it feel weird. The purpose of them is clear: delving into religious psyche, in this case the way of Path. This is fitting for speculative fiction. I only wish he would have chosen a more similar religion. Whatever, all is well enough.
When I've finished the book, I'll be sure to post a full analysis. I can't think of much else to add thus far off the top of my head.