Here are my thoughts on why the n900 failed. When the n900 launched it was 650 dollars when one could buy an Archos 5 and install sde (special developer editon firmware) and a smartq v5 for less money and you would have just as much hackability and openness, you could also buy a UMPC like the Viliv n5/s5 or the Umid m1/m2 for the same price. The n900's screen is only 3.5inches, that would perfectly fine if Nokia was making a mainstream smartphone but they weren't making a smartphone, the Nokia Internet Tablets were designed to be Nokia's answer to Archos, SmartQ, Viliv, and the rest of China, 3.5inches doesn't make a MID. Also the thing had smartphone functions, what but this thing is two handed like a MID and it lacks basic phone functions like mms? The n900 didn't have 4 row keyboard or 4.1inch screen like the n810 and there are many who like the n810 form factor so that kills a very large chunk of potential customers. The n900 was the typical lets cram 1,000 functions in one device and not try to make all of those functions work well (Nokia does that a lot), the n810 was the exact opposite that. What Nokia should have done with the n900 is a make a MID or a mainstream smartphone rather than trying to make a device that is both (Dell on the other hand was successful at creating a device that was both phone and MID with the Streak). My thoughts.
Recommendation: While it has yet to reach its full potential, the Nokia N900 is a powerful mobile device with excellent browsing capabilities and vast customization options. However, its unintuitive interface and other limitations make this a smartphone for tech enthusiasts and early adopters only.
Speed + Performance.The Nokia N900 is one of the most powerful phones on the planet. It's a computer in your pocket that allows you to communicate in every way imaginable.
With a customisable interface, great multimedia features and capable browser, the N900 is far better than any Nokia handset we’ve seen in along time. In terms of browsing and sheer multitasking capability, it’s also superior to other smartphone rivals.