Funny. I have the opposite feeling. I find the N900 and excellent piece of hardware. Maemo5 is, IMHO, not on par.

But if you want to use the N900 fully (i.e. also as a phone), we're pretty much stuck with Maemo. My current efforts (though very slow due to lack of time) is to try to "Linuxify"[*] Maemo as much as I can, while keeping the useful bits (e.g. being able to make a call).
[*] In the good sense of the word. Like Linux about 10 years ago or so. Before it became a bad copy of Windows and MacOS.