As I'm using a HTC Hero right now, this is what I can tell you:
- multitask is nowhere near to Symbian or Maemo. It is up to Android to decide what it allows to run longer and for me it turns out to be the wrong decision more times than the right one.
(It closes apps when it shouldn't or keeps apps running, when they should shut down - draining the battery and running my roaming charges high.)

- Adobe Flash, although very close to what was shown for Maemo 5, still misses quite a few online video players. Not a big difference, but I prefer sg, which is closer to full web experience.
(Flash 10 was demoed first on the N900.)

- the 5 MP camera (no photo flash!) is a toy, compared to the Carl Zeiss lens. My older 3 MP (CZ) lens make better pictures than the Hero's, not to mention that I can somewhat use it in the dark too.

I don't want to convince you, as the rest is pretty much up to par b/w Android and Maemo - but I'm switching for the Nokia hardware and the multitasking from Android to Maemo.