I finally got around to building some docs for our latest project, and decided to go with Sandcastle rather than NDoc for the time being. I got the March CTP of Sandcastle and started trying to figure out how to get it working with our build.
While the resulting CHM file came out looking really nice, I'd have to say that Sandcastle is WAY not ready for prime time. There is little to no documentation, so figuring out how to customize things is largely an exercise for the user. I was willing to exercise, but many aren't. The build itself is very complicated, with 10-12 separate steps required to produce the CHM file, and lots of rough edges, like the fact that the MRefBuilder tool won't look for dependencies in the GAC, so I had to copy a bunch of core BCL assemblies out of the GAC and into my build directory to get the docs to build. Lame.
As it stands now, Sandcastle is useful only to serious build weenies, since it's too cumbersome for the average developer to deal with. This is too bad, since it's being touted (at least in some circles) as the "right" solution for building docs going forward. It smacks of something that the VS 2005 team built to create there docs, then decided to make public. It's not quite there yet.