I don't really care how much more "open" Android or Maemo are... they're both closed to some extent.

The difference I see is with the parts that are actually open:

Maemo: mostly "copyleft", which means you are not allowed to take the open code and distribute it as closed source.

Android: non-copyleft. Whoever packs it on a handset and sells it may well throw the whole open source idea overboard and distribute it as a closed, locked, non-free binary. (exception: kernel and a few low-level components)
This is exactly what handset manufacturers want. This is exactly what they do with Android. And this, in turn, is the reason why Google chose this licensing model for Android in the first place. They know most manufacturers aren't ready for free software the way Nokia is. They want to get the benefits of the free development (like Motorola - they benefit from Nokia's work on the kernel, as I learned here), but they don't want to get their hands dirty with community involvement and open platforms and stuff.

That's one difference.

The other one is that what Nokia does for Maemo improves my user experience on whatever GNU/Linux desktop distribution I use. Can't say that for Android, which is a different planet from a technical point of view.

That's what counts for me. Not how many lines of the original OS I can download, read, compile, whatever.