Here are some thoughts and experiences about the Nokia N900, now that I have had time to play with it some more. I'll add more in a week or two later when I've been carrying it around more, but I want to write this down before I forget the flaws and get used to the awesome.
The Bad
I'll begin with some of the problems I've found (mostly minor) before going onto the cool stuff.
First of all, the multitasking. Yes, it does multitask and its GREAT, but those of us who are used to 4GB's of RAM and keeping all your applications running all the time... Yeah, don't do that. You'll find a balance after some trial and error and the apps start fast enough so you don't have to keep them running all the time. The good thing about the full-featured Firefox is also the problem - you end up trying to run JavaScript heavy web-apps in the background which will eat memory (since they are designed for the 4GB machines) which in turn will make your phone lag.
What you also notice when you use the browser is how heavy the websites and web apps have become, I hope web-developers will start to accommodate smarter phones, NetBooks, TV:s and other less powerful browsing devices soon. There needs to be something in between the standard mobile-version of sites and the full experience.
The kernel in general needs some tuning when it comes to lag and priorities I think, sounds can and will skip at times and things you'd imagine should have priority doesn't. When I leave my apartment the phone moves all data-connections over to 3G from my home WLAN, which is brilliant, but at the same time I'm trying to start playing some music and the media-player interface becomes sluggish. Mind you, at the same time I probably had a bit too many programs running anyway but still.
The above mentioned media player needs improvements on both interface and functionality I think, it doesn't work very well on the move and there's no quick way to stop the music (though, as you'd expect it pauses if you get a phone-call). If you unplug your headphones it'll start playing over the speakers instead of pausing like the iPhone/iPod touch does, which can be a cause for embarrassment... Especially when you have to start unlocking the screen, task-switching to the media player and then, some eternally long seconds later, getting the music paused. Also its one of those things that the iPhone does so well.
Speaking of what the iPhone does so well: Applications. Yes, it's extremely unfair to compare Maemo 5 to the iPhone App Store but you need to know that nowadays there's even a big drawback on being the first on a new platform, the software and the developers won't be there yet. All this will, hopefully, change but until then - if a terminal and great browser isn't going to be enough for you and you need a shiny twitter-client or photo-editing software - don't buy an N900. That said, lots of what you'd use a little iPhone app for can be done using the browser already. I've ended up using twitter a lot less and that's mostly a good thing :).
The Details
Skype and IM on the N900 is brilliant, but if you plan to use the N900 in always-online mode, you need to rethink how you use IM and how your friends use it. The biggest problem was that I used to be on a few high-traffic Skype chats, on the desktop-client you can stop notifications from specific persons or groups. Not so on the N900: which meant that I was at lunchtime bombarded with discussions about where and what to eat. Notification sounds and all.
The Ovi Maps software is a bit weird and not very useful. It does what its supposed to if you want to go from one place to another but you might have to search for the place you want to go to twice and you can't (or its hard) to save positions , etc. The Symbian version of Ovi Maps is supposed to be a lot better so there's hope in the future. Also I'm sure we'll get a native Google Maps client soon enough.
The included headphones, Nokia WH-205, are surprisingly good in-ear headphones. As an added bonus they are dark and without any visible logos, great for those of us who don't want to advertise that they carry expensive electronics around. The cables are flat and supposed to stop them from tangling up, we'll see about that. Haven't kept them in my bag or pocket yet so not sure. Built in microphone for hands-free action of course. They are different from iPhone hands-frees though - the pin-outs are different, which is sad because there are lots of high quality alternatives coming to the iPhone. Normal headphones work on the N900 of course.
I like the camera's picture quality, even though it could probably do with a little better post-processing, especially considering you have the horsepower to do it. What is annoying, however, is that the camera has three different lag-points, it takes time to start the camera, it has a pretty significant shutter lag, but the weirdest thing is that it has a lag on the shutter-sound too - which comes seconds after the picture has been taken. Only after a surprisingly long post-processing can you see what you actually caught on camera. Better than most mobile cameras, for sure, but still iI feel it could be better just by improving the software. On a positive note though, the geotagging is insanely fast. It has a GPS-lock before you are able to take a picture.
If you are getting an N900 and will use the terminal, make yourself a favor and install the droid font pack, it's the same fonts that Google uses in Android and they are gorgeous - especially "Droid Sans Mono" at size 10 as the xterm-font is the best! You get a super-readable 24x100 terminal, on your phone!
The Good
Well, the good thing is that most of the bad things can, and will (hopefully), be fixed via software updates and additional software. The rest is details you get used to.
I like the build quality, the more I use and hold the phone, the more I like it - basically getting used to its heaviness. The casing is built like an IBM/Lenovo ThinkPad, you could probably kill someone with it. The design, now that I think of it, is also of the understated ThinkPad/Darth Vader-kind. When holding it in your hand, especially with the keyboard out, it has lots of gripping areas so you don't have to be afraid of it slipping out of your hand. Haven't tried dropping it yet but since the screen is not glass and it generally feels very sturdy I think it might survive a drop or two more than an iPhone.
I'm also getting used to the keyboard and already typing pretty fast with it, I'm finding myself using it even for longer discussion on Skype. Speaking of Skype, voice-chatting over Skype works quite well (over WLAN, yet to try it over 3G). Sounds are a bit muddier than normal voice-calls (which are crystal clear, just as you'd expect from Nokia).
I've been using the phone with the Internet-connection open all the time (SSH-connection open, chat and email open) and the battery life is pretty decent. With heavy use on friday I used it for around 7 hours, mostly on 3G. I took a few phone-calls, browsed the Internet, chatted on Skype, took some photos (geotagged using the GPS of course), uploaded photos as well as listened to music most of that 7 hours. When online using WLAN and not in heavy use (over night for instance) it hardly uses any power at all. Final verdict on battery life is hard to give though so I'll get back to you on that. In general it feels like it probably will be useful for the whole day but if you are going somewhere overnight you'll want to bring your charger.
I also want to reiterate the other good things I mentioned in the last post, the stylus is really practical at times even if its sensitive enough to be used with your fingers. The browser is top-notch, its even capable of running 1Password Anywhere which is a javascript-based decryption tool for your password (very useful since I use different passwords everywhere, thanks to 1Password on the Mac). Should note that it is pretty slow though but usable. The xterm is excellent, especially after switching to the droid-fonts as mentioned earlier and the camera is good. Sharing and tagging the pictures really is easy on the move and the uploads are done in the background.
All in all I'm still very happy with the N900, it is in the early days of its software so owners have to be a bit patient but it really is great and the future potential for greatness really is there.
ps. Please remember when you look at the screenshots that on the device itself they are only 3.5", so they are small and incredibly sharp!
Click the picture to see it in Flickr with geotagging enabled (and uploaded on the go):
http://www.flickr.com/photos/hagge/4746606664/ 
