I own a 9110 and a 9210 (havent sold the 9110 yet, I like the idea of a backup phone).
I think the 9210 is a great device but I'm concerned about the lack of knowledge and conflicting policies with Nokia here in Australia. I bought my phone in Singapore and (of course) was promised that all warranty work and upgrades etc could be carried out in Australia. There has been no problem with warranty but I have had some Nokia people say I have to send it to Singapore (not true). the issue I have is that Nokia automatically upgraded my firmware to version 4.13 and whether they stuffed the upgrade or there is a compatibility issue, all data including my backup (on the mmc) has been lost. I have my contacts thankfully (185 contacts take a long time to retype) but everything else is gone. Nokia say "sorry, but it happens sometimes" and due to travelling often I don't have a current backup on my PC. The memory usage is showing that the backup files are there on the mmc (2.8Mb unnacounted for) but I can only see the folders using windows explorer when linked. This is frustrating because I can't work out if I can use it for a restore or just delete it. All the installed apps are still showing as being installed but I can't access them so I suspect there was a glitch with the upgrade. I don't know if anyone else has had a similar problem or can offer advice. Sorry for the long-winded post .
Upgrade problems
First thought is try the MMC in an MMC reader, another 9210 or even a PocketPC device to check the files aren't there and that it's not a glitch with the 9210.
Regarding the phone format the internal memory (something like hold Ctrl-Shift-F or Ctrl-Shift-Chr-F on bootup) and see if that helps. This sometimes solves problems as originally my 9210 fell over a lot or the keyboard wouldn't respond, a format and reinstall and it has worked perfectly since. Seems a small corruption in the ini files can take the PDA side out completely.
If the format fails, get the firmware flashed again as that should solve it if it's the problem.