None of those run Maemo..
And none of those are as configurable as the n900.
Sure better devices for the masses but not as powerful as the n900. Sure the n900 got places where it lacks and when those are covered i will switch... but i fear it will take time until that is met.
Are they capable to run a full fledged desktop OS like Debian/Ubuntu/Fedora as good as the n900? How long do they hold the battery? Can you overclock them as easy?
But true.. this is not a black and white opinion.. In my mind there is no better device out there yet.
Think different :P
can you do this with any other geekphone? If so, I'd be interested: - view and edit text files, in their original format. This is my main use for the N900: I look up medical information contained in text files that will replace cumbersome medical textbooks. I run vim and search for keywords in text files over 10 MB in size (yes, 10 MB of text; we're not talking a 10 MB PDF or a 10 MB JPEG file which contains much less useful info). Previously I used the Palm Treo/HandEra/TRGpro which could edit text files but you'd have to convert it to/from the Palm text format, which is still not too bad... - replace the user interface with a modified version (modified Linux kernel, modified Hildon interface). Bonus points if the modified version is open source so you can trust/modify it. - use Python with libraries that let you hook up to the DBUS interface so you can control other applications. (Other systems might require use of C/C++, which might be okay for others but I find Python much easier to learn and keep up with.) - backup to my home server via online Internet access, so I can do a backup while I'm taking a walk in the park, and feel secure knowing that I have a backup copy of the priceless video I just took of my kid. - do shell scripting. Bonus points if it's (pretty much) the same Linux shell that you're already used to using on your desktop.
These are things that are unique to the N900 that made me buy my third one even after I found the first two defective..