Office 365 (Enterprise) problems and limitations

Everyday my list of issues and limitations grows.  I would reconsider moving to Office 365 at this point, its definitely not ready for Enterprise deployments.

1. Federation setup (aka Single Sign On) is a mess to deploy and requires an investment in servers (2 at a very minimum not including the Exchange server) and keeping them stable just to use the service.  Microsoft recommends 6 servers, which at that cost and infrastructure administration it's actually cheaper and far easier to setup your own Exchange server.
2. Migrating from an existing Exchange setup will limit you later on and requires a complex setup.  Furthermore it's nearly impossible to administer Office 365 without an on-premise Exchange 2010 server.  So don't assume you will never need to host an on-premise Exchange server once everything has been moved over.
3. Problems with DirSync's one-way push breaks a huge amount of functionality.  For example, you cannot use self-managing distribution groups they way they were intended.  All changes have to be done by an admin to the local active directory then pushed to Office 365.
4. The "free" licenses for Room/Shared mailboxes must be created on Office 365 -- migrating them from an existing Exchange server is a disaster and extremely buggy.
5. The free "Shared" mailbox limitations are overwhelming.  You cannot use IMAP/POP3 and they have to mapped through the users Mailbox account.  Because of this, you cannot create mail rules since you do not have the ability to login directly to the mailbox.  The OWA/web-version rules are nearly useless (can't create autoreplies/forwarding/etc).
6. Migrating mailboxes is hit or miss.  About 1 in 10 of our migrations (300 accounts) have encountered errors where email properties are not updated causing duplicate mailboxes on both the on-prem server and on Office 365.  Without dirty hacking ADSI, the only fix is to completely remove both emails accounts and start over (which makes a huge mess for users since replies from their old emails will bounce due to broken x400/x500 and GUID differences).
7. Tier 1 support is absolutely useless.  I have 25 open tickets (some 2+ weeks old) and their replies have never resolved anything. Sadly, unless you request escalation they will respond with completely irrelevant links or information, then request you update the ticket since to them it looks like the ticket is now waiting on you.
8. Mobile device support is disappointing.  Blackberry devices are not supported at this time.  Android phones running 2.3+ cannot sync with their servers (yet worked fine with Exchange 2003/2007)...
9. If you are running any LDAP mail-lookups you will find sometimes its impossible to replicate some email address you have in Office 365 back to your local Active Directory.  So if you plan to use this with a local Sharepoint on-site, think again.  Same goes with using their server as an SMTP gateway.  They require TLS encryption with an existing account, so using it for your scanners or email alerts will require you to run your own local SMTP gateway.

The only benefit out of this whole fiasco was giving users 25GB mailboxes.  But after using Office 365, I can honestly say it's far easier and cheaper to setup your own Exchange 2010 infrastructure.  Until they find a better "DirSync" solution, the limitation with having to make changes on-site is too limiting.  The requirements of Federation authentication is such a huge burden and overhead, that its initial time to setup and hardware requirements alone are just as complex and massive as running your own Exchange server.  It was a decent attempt, but this service is definitely for Small Businesses only that do not require single signon!  Be warned!

Update 4/5/2012:  More issues I've encountered:
1. Lync (their IM solution/Goto Meeting alternate) does not support delegation in Office 365 (but is supported in their regular versions).  By this I mean an administrative assistant cannot create online meetings for their supervisors.
2. I've had a problem where their database was not mounted for a user.  Took 2 hours on the phone with tech support before it was finally resolved.  They couldn't figure out the problem nor how it was magically fixed.
3. As a workaround for using shared mailboxes, we've been using IMAPS for our workgroups.  Unfortunately they changed some server settings recently and now IMAP connections are limited to 1 concurrent session PER USER.
4. I've discovered inbetween SP1 and SP2 a lot of mailboxes have lost their GUID mapping with active directory.  I've had to manually readd the GUID if the user's mailbox needed to be moved back to the on-prem Exchange servers (for example ex-employee's mailbox that needs to be backed up).
5. Archives.  You cannot access archives through OWA as the user or an admin.  You must make an automapped account in Outlook to access it which goes against their recommendation for shared mailboxes.