Don't need to contribute more to this flame war than: I agree with most of the criticism. This is a bad move by MS.
But let me add something to the confusion. I am in the proces of setting up an infrastructure with two DC's, two files servers, two app servers and ... two dedicated Exchange servers. All virtualized using two VMware hosts. All running R2. After installing the DCs and file servers, I installed the first Exchange virtual box without much problems. It was when I installed the second, when the shit hit the fan. But only when installing the mailbox role (data area too small, or something).
But .... CAS and Admin tools seem to work.
After several tries (among others a step by step installation) I gave up and installed the <sarcastic>old</sarcastic> 2008. Now everything seems to work. So one Exchange running on R2, the other on the vintage 2008.
I even tried upgrading the latter to R2, but the installation couldn't continue unless I uninstall Exchange. Which I then didn't.
Do I dare to go into production with this setup? I think not. I'm afraid I will have to reinstall my R2 Exchange server.
I wonder what the solution will be for small businesses. What I read about 2010 is that this may only be useful for enterprises so they'll be stuck with this situation. Or am I misinformed here?