I've been getting to know the N900 since last night when I unbricked it.
Screen -- The Good
The screen on the N900 is beautiful. It's bright, colorful and very readable. The N900 screen is transreflective so it ought to be very readable in bright day light. The surface doesn't feel like glass (like on recent iPhones). I'd be surprised if it were, as we'll see below.
The N900 screen is also very pixel dense for a device of this size. At 3.5" it's very large though smaller than the 4.1" screen on the N810. Screen resolution is 800x480 pixels. Despite being physically smaller than the N810 screen it's very readable. And one thing I've found so far is that double-tapping in the web browser causes it to zoom in on the text your reading. If the N900 couldn't zoom into what I'm reading I'd find it very hard to read many sites due to the small screen and awesome pixel density.
Screen -- The Different
If you haven't heard yet, the N900 has a resistive touchscreen rather than capacitive. In a nutshell, resistive screens require a slight amount of pressure to register clicks and movement where as capacitive screens require contact with something a slight current of voltage can pass through, e.g., like your fingers. The advantage of resistive screens is they don't respond to a light brush of your fingers and do respond to non-conductive surfaces like stylii. The disadvantage is resistive screens don't respond to a light brush of your fingers. And so far I haven't seen any resistive screens that are multi-touch capable. I.e., no pinch zooming.
If you've played with an Apple iPhone or the Motorola Droid you know that browsing through web pages or a long list of contacts in the address book is quick and simple: just brush your finger across the interface. With a resistive screen you have to push slightly to register contact and then move your finger. The need to push, however so slightly isn't always easy.
Initial Conclusions on the Screen
On the whole I'm happy with the screen on the N900. It's going to take some time getting used to the resistive screen. I'll have more to say about it I'm sure.
The keyboard on the N900 has 3 rows. That's significantly fewer than previous version of the Nokia Internet Tablets. The keys are flush against each other making key travel a bit tight. There's also no for navigation. Rather the keyboard has the very familiar inverted-T arrow keys.
Despite fewer rows in practice I think the N900 keyboard will be usable. What you lose without the fourth row are the dedicated numeric keys. They're function-shifted above the first line of the qwerty keyboard. I've typed a few odd lines and while I wouldn't want to write a long missive I'm pretty sure typing short email responses, text messages and the odd online post should be doable.
Body and Slider
The N900 body and slider feel very well constructed. The body is solid and the slider moves with a very solid click. There's no wiggling, creaking or give when pressing the screen or keys unlike the N95 which despite being a fantastic device felt a bit flimsy for it's $500 price tag. The N900 is solid though it lacks the truly impressive feel of the Nokia E71. The E71 is truly one of the best if not the best feeling phones I've ever held. It really reminds me of the original Palm V. I carried a Palm V in my back pocket for almost 5 years without a case. That's the same way I carry the E71. While I don't think I'd carry the N900 in my back pocket it does feel solid enough.
The black color, smooth texture and rounded corners are all very appealing. Couple with the bright, beautiful screen the N900 has great curb appeal. If I had an complaint so far it would be the battery cover is a bit hard to pull off and feels a bit cheap — not flimsy, just cheap. If it were up to me the N900 would have a similar cover to that of the E71.
Kickstand and Camera Cover
While I'm not excited about the heft of the battery cover it does retain a favorite feature from previous Internet Tables: the kickstand. Since the original 770 the Internet Tablets have all included some way to stand the device up on the desk for easy viewing. The 770 included an external stand while N800 originated the built-in kickstand. The N900's battery cover includes a remarkably different stand. Whereas the N800 and N810 had kickstands that stretched from the left side to the right, the N900's kickstand is isolated to just the area around the camera slider.
Like previous Internet Tablets the N900 is primarily a landscape-oriented device. The original 770 had several buttons along the top of the device. If I recall correctly the left rocker was specifically for zooming in and out and the middle button was for toggling full-screen mode. The N900 rocker appears to be mostly a volume control though in the browser it controls page zooming. Toggling fullscreen now seems to be a function solely of a software button in the lower right-hand corner of the device.
The power button on top like many Nokia devices both turns the device on and when running pops-up a menu for common power-related functions.
There's also a spring-loaded button on the right that turns off the display and locks the device. If you slide it again it turns it back on immediately without requiring you to move an on-screen slider or unlock the device. (Perhaps with a security code set it would.)
I can't say much about battery life yet. I'm a bit concerned about such a small battery. At 1320 mAh the BL-5J seems a bit under-powered for the N900. I would have preferred the beefier 1500 mAh BP4-L of the E71 and N810. 180 mAh don't sound like much but every bit helps. It's also interchangeable with the previous Nokia Internet Tablets as well as the E71.
The N900 is the first Nokia device to sport Maemo 5. Maemo 5 is quite different from previous versions of Maemo. The immediate differences I see are the left-navigation bar is gone, along with the Home menu button as well. There's a button in the upper left corner that takes you to a directory of all your applications. When running an application pressing it will take you to an intermediate screen where you can see all your running applications. Clicking it again from there takes you to the list of running applications.
Unlike previous versions of Maemo, version 5 supports multiple desktops. You move from desktop to desktop by swiping left or right. By default there are four. The default install has various buttons and applications on each. One desktop seems to be the Ovi screen with links to Ovi Maps and the Ovi store. One is the social media desktop with links to Twitter and Facebook. Another is the PDA/Phone screen with links to the address book, calendar and phone application.
A Phone Application
That last application is the interesting one. The two the most desired features of previous Internet Tablets were always always-on internet and phone, though not necessarily cell phoning. The N900 seems to be sticking to its heritage as a multifunction Internet Tablet. Making phone calls is just another application and the phone application isn't on the home desktop. The web browser is but the phone is on the next desktop to the right. Nokia seem to be communicating very clearly that the inclusion of a GSM radio is more about providing 3G+ internet connectivity than telephony. And while I haven't tried them yet, the N900 provides more internet-based phone-calling options in the form of SIP, Skype and others than traditional cellular.
To further emphasize the N900 is not a phone with internet access there are no dedicated buttons on the device for telephony. There's no Nokia-green call or red hang-up icons or buttons any where to be found. They're in the telephone application.
I've only begun to dig into the N900. I don't have time to test it out thoroughly as a phone, contact manager, calendar and internet tablet so I'm going to start with the latter. I don't know for how long but for now I'm leaving my SIM and contact list in my E71 and I'm going to use it as a wifi-connected internet tablet and write up my thoughts from that perspective first.