I've had a chance to digest OpenID and what it brings to the Internet. Technically I think it works quite well, but may need some rework if it's popularity picks up (caching, etc).
As somebody who is starting a venture, the true value in OpenID is the "free" user base you have access too. There are already 9+ million OpenID users thanks to LiveJournal, and Zooomr adds more still. Anyone that implements OpenID conceptually already "has" these users as part of their service. The complication is that because of OpenID's limited public awareness, anyone who brings OpenID on board now has to also explain the concept of OpenID instead of just issuing the standard user/pass spiel. Also, unless existing OpenID aware sites told their users about my site, I'm not sure if I could warrant the extra confusion for my site visitors... I guess there is a bit of a chicken/egg issue after all.
Besides the existing 9+ million user base, another interesting aspect of OpenID is that it's a great way to align companies to share a user base. This leads to interesting opportunities like cross promoting that can be mutually beneficial to all involved companies. I think if I can align myself with other companies then OpenID is definitely the way to go, and OpenID gives me leverage to approach other companies to partner with.
Technically OpenID is great, and you can even run it as a complementary ID system to your sites standard user/pass. However, it's immature adoption is holding me back from accepting it 100%. If I can align myself with others then OpenID is a good way to do that. If you're open to teaming up with a new fangled personal communication system (think IM 2.0, but not), then please contact me!