I've now been playing with my n810 for a full month and I seriously feel like a beta tester.

• I have to backup, reformat, and reinstall the internal filesystem due to a corruption bug. How this bug managed to get into shipping units baffles me. The fix is via the command line and there is no official support for this bug/fix.
• Out of the box Application Manager lists Maps as having updates, but is unable to actually install it.
• Addressbook: Can't handle some basic vcard syntax so it's impossible to import an extract of my Mac addressbook.
• Default email client inoperable with major providers like gmail imap
• Built-in IM unable to do some very basic operations like status messages
• Interface is inconsistent at best
• Not finger friendly
• WiFi performance is marginal to poor with real world performance between 300 and 500 kB/s.
• WiFI will not auto-connect to WPA-Enterprise networks, I have to manually reselect them every time. My unit works with open, WEP, and WPA-PSK networks without a hitch.
• GPS and camera... I don't think I need to elaborate on this one

Those are issues solely with the stock firmware from Nokia. Many people here have suggestions for dealing with and working around these faults in the stock software, so I'll cover them here.

• Pidgin/RTcomm beta: Pidgin on maemo development appears to have ceased as bugs that I found almost a year ago are still unfixed. While a little tricky to install RTcomm beta has been the most stable add-on that I have used to date. That being said it's screwed up my address book on more than one occasion as well as having other major issues which have been reported.
• Modest/Claws: Modest, while mostly functional with gmail, has not seen a stable release since I received my unit. I have not yet tried claws because it doesn't appear finger friendly.
• App Manager: Once again it's refusing to install/update applications because of a repository conflict.

There are a few bright spots in all of this. The browsing is excellent most of the time with only the occasional crash. The built in SIP client works very well, better than many desktop tools I have used. I will probably keep the unit for now, but the issues that the n810 has have been disappointing.