I recently used my N900 for a day--just to see. It still holds up. I do love that device, and if something happened to my N9 I would go back to it and stay with it. But I have a working N9, so I don't. The big drawbacks for me (N900) are the less than vibrant screen, the 3G seems slightly slower, the stock browser is just old and Opera/Firefox are not better, the slow processor, & the lack of or half-assed portrait support.
But Maemo just makes more sense than Meego, the UI is perfect. And it's so flexible. I really miss some things. I almost wish I was forced to go back. I know--stupid. What I really want is a 7-inch tablet with the Maemo OS. I really do.