Thank you, Silicon Valley, for voting overwhelmingly Democrat and bringing this and other business killing legislation here in California and countrywide.
Depends what you want to build...
1. Do you want to build a pretty state of the art community focused more on the content than on unique features - than it could be a good choice
2. Do you want to build a unique feature driven site? - maybe a traditional framework would be better
3. Do you want to take an agile development approach to building your community - it is a good choice
I would recommend putting your site concept out to the drupal community and getting advice from them (drupal.org)
Well, first of all, that's not strictly true. I've recently joined the Drupal community, but I really like Rails and wouldn't hesitate to recommend it to the right person.
But, more importantly, when a member of the Drupal community inevitably urges you to use Drupal, they might also give you specific bits of invaluable advice like "oh, that thing you're trying to do is just Drupal core, plus CCK, plus Views, plus Organic Groups, plus Imagefield/Imagecache. Oops, except that Imagecache assumes X and you want Y... you'll need a bit of custom code. This other thing you want to do is 100% custom code. And those fine-grained permissions you want will add an extra 100 queries per page for logged-in users -- they'll stop working as your paid userbase grows, so remember to hire a hacker to re-engineer them if your app is a success. And make sure to budget extra time for theming, because it's a bear."