Being a writing geek, I own a Nokia E90 and I have owned the E70 before it. On these two devices, Nokia managed to make an exceptional work at keyboard quality. Symbian is horrible but I have customized it enough so that it almost never gets in the way, plus I have the right applications for everything.
As to your question: my personal reservations about the N900 involve the usual Nokia build quality. The stick was horrible on the E70, the E90 has a shell that gets creaky in my hands.
Other than this, both were fine devices and probably the top at the time when they were out, and to me the E90 is still more evolved than most of the current devices: I can do everything with it, from very quick writing (close to computer keyboards) to MSN/Google Messenging, browsing. Ebook reading, gameboy advance emulating, dictionaries, tree-based organizers, and much other stuff. The keyboard is huge and full of any kind of shortcuts, not just those available by "factory".
Personally, looking at how I grow accustomed at using the E90 as an "extention" of myself
, I consider the N900 the only viable upgrade for me at the moment. The Maemo OS looks awesome and the sexiest among what's available now. It won't be long before you'll see many advanced programs (there is even a Nintendo 64 emulator under development), including powerful and fast office suits and what's not. The potential the device has will attract freeware developers to make it the ideal "geeky" platform.
I will probably wait for something even superior (I'd like capacitive screen with even bigger resolution - netbook resolution if possible - and a processor as good as HD2's or even better), but this is the only "phone" that I look at with interest/lust.
The HD2 has many good aspects, mostly the power, screen and WM overhaul, but it misses a fundamental aspect for me: it doesn't have a physical keyboard, and as such I would be unable to use it smoothly for the largest parts of my needs.
The Droid comes out as the least interesting of the three, for me, because it's keyboard is not very good compared to what I am used to, and processor is lower than that of N900. I admit, anyway, that the Maemo is the biggest reason for I am interested in the Nokia, since it's basically a full blown OS in a *tiny* package with big battery life.
I hope my view can help you out.
Tony
