Getting back to the topic (briefly), I believe the guys over in our d20 "topics" line had advanced access to D&D 3.5, but frankly, I never thought to ask. I just follow along here out of mild interest. I haven't worked on a D&D product for a couple of months, so I knew my stuff would be off and gone before 3.5 became a pressing issue. The change over to 3.5 will, so far, have one effect on
Spycraft that I can see: I'll probably errata Weapon Finesse to resemble the 3.5 version. More wham from Power Attack is right out in my opinion, but then again, I deal in a game where I'd get asked why Bullseye (sort of like Power Attack for guns) doesn't do extra damage if I hold the gun in two hamds...? Just not worth the trouble

.
On the subject of fragmentation, I'd be concerned too. The introduction of LR5's second edition gutted the players base, because while there where changes that were clever and lead to better play, there were also clearly changes for the sake of changes. That left some people playing one game, and some playing the other, both for very good reasons. A new player never knew what kind of answer he'd get on a rules question, or if he was about to set off a massive debate asking about one of the contentious changes. All-in-all: Ugly.
The accusation of changes for the sake of changes can and has been leveled at 3.5. I don't have Monte's behind the scenes insights, but I do make my living writing d20, and I've -studied- as many books as I can lay my hands on, hard. There are some subtle reasons why things were done the way they were - not always with explinations given, but they do reveal themselves in play. Some of the changes in 3.5 make me itchy. That tells me than Monte's 90% switch over in a perfect world is a reasonable best case figure, and it means that newbies are going to ask "What are you talking about?" when somebody discusses a druid different than the one in their book. It sounds like a triffle, but trust me, it harms a game. It certainly puts smaller publishers in an awkward spot. People talk about aving conversion notes and sidebars in their books to make both crowds happy. I promise it'll be a cludge at best. The L5R dual-stat books never fail to take a hit from reviewers because somebody isn't using some part of the book, but that "other system" is taking up precious space. Were I a prgnosticator, I'd predict a sharp decline in the number of barbarian, druid and bard NPCs in 3rd party adventures for a while... Why step on a land mine when you don't have too?
Oh, and for the record, I'll be picking up AU so I can puzzle apart all the systems in it

, and downloading the 3.5 SRD out of my continuing idle curiosity. They both look like interesting reads, but one I can get for free.