<p>Our team is setting up nightly and continuous integration builds.  We own Team Foundation Server and could use Team Foundation Build.  I'm more familiar with CC.Net and lean that way but management sees all the money spent on TFS and wants to use it.</p>

<p>Some things I like better about CC.Net is the flexibility of notifications as well as the ease of implementing custom scripts.</p>

<p>If you have experience with both products, which do you prefer and why?</p>

We've been using CruiseControl.net since June '07 and it's worked great for us.  Best part, it integrates to SVN easily which is a far superior source control provider.
So our setup is:
Cruise Control.Net
SVN
Trac
- for bug reports and project management (integrates perfectly with SVN)
nunit - for unit testing
We've had some major parallel development going and the branching and merging experience was spectacular.  If you have the choice I'd go with the setup above!