I think you summed up the benefit pretty well. You have to play in the ball-field that you are comfortable with. Windows 2008 R2 can support DNSSEC and it is a relatively good server platform.
I'm not sure if I would go that direction, but I cannot say personally that it would be a bad direction to go. The bigger question is does your in-house staff have the expertise to deploy this solution and keep it secure and available. I would think you are going to stage this before you go production, why not put this side by side against some of the other options you are weighing? What other platforms are you thinking about serving DNS?
DNSSEC Deployment Guide
EDIT : Added URL for Windows DNSSEC Deployments