Earlier quoted context omitted.
Unless your product is something that builds on Twitter's platform, I wouldn't recommend it. It means your users don't have a choice about how they're authenticated to your site, and A) Failwhale, anyone? B) Twitter doesn't provide serious options for protecting their users' login credentials. It's the same username/password combo which is easily phished & replayable. Sadly, I've pretty much given up on the hope that…
From a dev's point of view I really feel that OpenID/OAuth is absolutely not worth the headache. I'd rather just go the hacker news model. Choose a strong password and if you forget it, we send a new one to your email address. Works fine, offloads a lot of security issues to email providers (who tend to be good at it), easy to code.
I use Hacker News with OpenID ;)