It's the closest thing to a pocket sized computer/phone hybrid there is. I don't use n900 as a daily device anymore but I use it for doing fun and hacky thing that are impossible with android and ios. I simply love the freedom to use it similarly to how I'm using my desktop Linux box. To me android, ios, etc. are all feature phone operating systems with way too many limitations. Besides I hate the 'functionality comes with apps' approach they have. Just take a stock maemo image and compare what you can do with it against android, etc.

Just my 0.02