<p>I'm thinking about using BlogEngine.NET to launch my blog. I'm a C# programmer and was wondering was BlogEngine.NET has in the belly.</p>

<p>Does it scale well? Is it caching properly? Is it memory intensive? Can you easily add/remove functionality?</p>

<p>I also accept any hosting recommendation :)</p>

I'm running BlogEngine.Net. I don't know about scaling because my weblog isn't that popular (yet). I'm very happy with it. 
I tried subtext before and I had some stability problems with it, it logged exceptions that I found hard to debug. I got an error exporting the database to BlogML and it messed up the order of my blogposts. BlogEngine.Net seems a lot more stable.
I'm running on a virtualized server hosted by a friend of mine. I have seen no performance issues but that might be because of the massive 15 visitors per day peak load. I've have some trouble where Live Writer posts blog entries twice, but I suspect this is Live Writer's fault.
I really like the extension model and the way you can drag and drop extensions on the design of your blog. There aren't much themes that support this yet but I created my own look and feel by changing the standard theme in about three hours.