Most importing difference to other Nokia top notch devices is the decent touch support on the N900. At last you can now drag anywhere without having to use the scrollbar (like on current Series 60 5th Edition devices). The scrollbar also fades away after scrolling.
There are several desktops that you can switch by dragging them horizontally - better than the Android ones that I have seen because you can actually go in a circle (so there is no most left or most right desktop).
Another cool usability feature is the absence of cancel buttons in almost all places, just tap outside of the dialog's area to cancel it. This sounds complex but feels very natural after a while.
The phone's contact list consists of two frames - on the right side you have shortcuts (0-9, ABC, DEF, etc) and on the left frame you see the contacts.
The browser is powerful (it's based on Mozilla) and even supports Flash out of the box, nice one.
On the hardware side I'm quite pleasantly surprised on the battery's long duration (take that Palm Pre ). The keyboard is also quite decent with a small but surprisingly good to handle space bar. Also the high resolution is well received (800x480 pixel).
There's bound to be shadow when there's light. First of all: when the phone starts for the first time it asks me for the current date, time and position. Hello, you can get all of this information from the network - please let me double check but don't bother me with this.
Even though dragging works everywhere, it's not really as a smooth experience like on Android or the iPhone. The UI clearly needs some more speed in that process.
You can only use the device in landscape mode - unless you're making a call, then it's the portrait mode. That's something I don't understand - why shouldn't the user be able to switch at any time? Also the contact list works differently in phone mode and in normal mode.
The device is quite bulky and heavy, but at the same it feels quite robust. Smaller would be better.
The phone's alarm clock is another subtle thing: when it goes off, you have two equally large buttons: one for snoozing, one for stopping. I want the snooze button to be simple and the stopping mechanism to be complex, otherwise I just hit stop by accident and go back to sleep unaware that I didn't hit snooze.
Icons... for the most part the Series 60 icons are being used. Some like their clean and simple appearance, some don't. I belong to the latter.
The software installation process is another somewhat annoying thing - the good part is the Maemo specific section within Ovi that's easy accessible from within the phone. Currently this is browser-based so when you want to install an application, the application manager is being launched (which pauses for a moment), then the installation process is started. When the installation is finished I remain in the application manager and need to manually exit it to return to the browser. What I want instead is an intelligent application based store: it should allow me to install apps directly (and provide me with an option to launch the app after installation), it should indicate me when I view software that is already installed, it should provide me an easy way to upgrade existing apps.
Zooming in the browser is somewhat fun at the first time but very annoying later onwards. You move your finger clockwise to zoom in and anti-clockwise to zoom out. At first the browser doesn't know of course that you want to zoom so the page is dragged in the first moments before the gesture is being recognized. Funnily enough this zooming gesture is only supported in the browser. Zooming into photos is not supported at all.
The screen of the N900 is attracting dust and fingerprints like no other touch enabled phone we have. Good thing Nokia provides a polishing cloth.
The WLAN handling requires bugfixing. If you have trouble connecting to websites (as we had), then go to the main menu > settings > Internet connections > connections. There you have to select your WLAN connection, press edit and then go forward until you see the 'Advanced' button. There you have to switch to the 'Other' tab and select another power saving mode. Simple enough for developers, but only very determined enduser will cope with that (14 clicks and one scroll action are required for this change).
You can code for the N900 using QT, good ol' Linux or Widget programming. It's also possible to use Java SE programming, however support for that needs to be installed by the user first (and it's not a trivial process). There is also an overview about the state of Java on Maemo.
Start by visiting http://maemo.org/development. The SDK runs only on Ubuntu Linux, but there's a virtual machine for Mac OS X or Windows as well.
In comparison to Android the development tool chain needs to be simplified in our opinion, but it's a good start.
The N900 is a definitive step forward for Nokia, but it is still somewhat lagging behind Android and iPhone. Nokia, please pay attention to detail, consistency and even more usability in the next release. A sleeker hardware would also be welcomed for sure. And please allow 'normal' multitouch zooming in your browser (like the HTC Hero or the iPhone).
The Fun Part
Nokia has released... well... some strange advertisements, have a look for yourself: