My personal review...
"The Good":
- Fast boot times
Note that it cheats; if you try to run any application right after boot it will show "Loading...". Even considering that, boot time is still around half that of the N950.
This is actually more useful that it sounds. It means that when the N950 and the Lumia are both off and I need to look something up, I turn the Lumia on.
- Universal home and back buttons that work.

"The Bad":
- Unstable
I've seen it hang on boot (repeteadly), hang while installing an application, hang while uninstalling an application, hang while upgrading to the newest release, fail to automatically check mail (for an entire weekend!)
- Total and utter lack of multitasking
Even the LOCKSCREEN is considered "another application" and if you lock the screen you lose your current minesweeper game. Try this, it's not an exaggeration, I'm completely serious.
Of course additionally the usual complains about not being able to load webpages in the background, to download files in the background, to wait for PDFs to render in the background....
But Maemo is the only mobile platform left that does multitasking right (and ironically, Windows Mobile <= 6.5), so I guess everyone is already used to this crap.
- Non discoverable UI
A relative of mine was not able to play music using the builtin Zune application because after launching it ("tapping on "Music&Videos") you get a screen with "Applications: YouTube" and nothing more. Not even a single hint that the application is a panorama and that you should scroll right to see the actual music and videos.
This relative eventually rejected the device and returned it to me.
- Poor battery life
Being less useful than a decade-old Palm handheld, one would at least expect astronomical battery life. But for some reason it is actually worse than the battery life on my N950....
- Useless volume control
It is already way too loud at minimum volume (1/30). I am yet to listen to music at more than 5/30 because I fear I will break the speakers. And you cannot set independent alarms / music volumes.
- Horrible audio quality
Not a WP7 problem I guess. But my Lumia sounds horribly worse than my N950. It always sounds distorted; maybe related to the above problem.