We're a Python/Django shop with a few ASP.NET/C# projects every now and again. We use Django CMS for many of our clients, but we've used Umbraco for a few. It was aweful, the interface is fine for editing content, but building and templating a whole site through a web based client is painful.

Trying to build extensions was daunting, especially with the free version, it seems like they have a Commercial version with a few more developer bells and whistles.

Version control was also a pain, because everything is stored in the database, including templates and styling, so you can't really version control that with an outside VCS (we use Git). And what you CAN put under version control is half binary files anyway, hello conflictville, population you and a bunch of binary conflicts every time you sync.

Overall, I'm in love with Django CMS, and .NET is an old lover whom I don't really want to talk to any more, but she's still in my phone so I know who's calling when she drunk dials me.