I doubt your'e going to get a definitive answer that suits your needs, without physically using both phones. What might make the 900 a winner for some won't necessarily apply to you, same applies with the droid.

But if you're a texting demon then the 900 kb is streets ahead imho after using both phones.

I can't comment on the openness of the OS as I haven't delved that deep, but if your tech savvy enough to feel that you'll use the potential on offer then it's the 900.

My advice would be take the various comments as a rough guide, draw up your own list of real requirements and go and have a play with both.