When you start the beta versions of Outlook or OneNote, you get a dialog box that says "Blah blah blah functionality requires Microsoft Desktop Search. Download now?" That seems dangerously close to using the Office monopoly to "tie" Microsoft's offering in personal search. Not only that, you don't even have an option of "Don't tell me again." It's either "Download now" or "Remind me later."
Personally, I use X1 for personal search and don't want to change. But for the sake of OneNote, I'd do anything. To add insult to injury, though, MS Desktop Search doesn't install on test machine! I just get an "access denied" dialog and the install quits, even when run in Safe Mode.