There's also something else, though most end users won't care about it as it doesn't directly affect user experience:

The licensing of the whole platform is fundamentally different. Both Maemo and Android have open and closed parts. With Maemo, open components need to remain open. It's illegal (for Nokia or other companies) to change/enhance them and distribute their changes/enhancements as binaries only. Android permits just that: While vendors are allowed to re-distribute Android with the full sources, the license doesn't force them to do it.

The difference for the end user? If a free component on a Maemo system has a bug, you can download the sources, change and re-compile them, install them on your device... done. (This is more or less what I did when I found I didn't like the layout of the OS2008 feed reader applet, so it's not only a theoretical thing.)
On Android, it could well be that the sources you download from the Android website are not what was used to create the binaries on your device. Bugs you experience may not be visible in the sources because the vendor applied changes. Even worse, your own variation of a (supposedly open) component may not run on your device because it depends on other packages that also have been changed by the vendor - and are incompatible now.

Compared to really closed systems, of course, Android is still relatively open... But Maemo is even better.