I was granted participation in the beta of Gmail for Your Domain and finally pointed my MX records there yesterday. Now Google is handling my personal email directly.
I recently switched from Yahoo to Gmail for personal email after Yahoo just became unacceptably slow and apparently less effective at spam handling.
Gmail for my Domain is excellent so far. The management interface allows one to create accounts, set and reset passwords (and force the user to change them), set up aliases, lists (based on the set of users in the domain) and monitor quota usage.
I'm limited to the number of email addresses I requested in my application.
I also confirmed last night that you can share Google Calendars with users in the domain since it lets you specify the full email address of someone you want to share a calendar with. It all just works!