It depends, actually. For stuff I write in my spare time, it's actually perfectly easy to write C# in Emacs and drive the compile with a short waf script instead of a solution. You'll pick up at least some csproj files if you grab packages from NuGet, but it's not horrible to manipulate them in nxml-mode, and again, it's easy to keep all of your own stuff in simple waf files.
The downside of going this route, of course, is that using VS.NET or MonoDevelop can be a bit of a pain. When working on Kiln, I instead do most of the actual editing in Emacs, and use VS.NET as a solution manager/debugger/decompiler. Not ideal, but functional. You'd also have to go that route if you wanted to use Azure, I believe, since I seem to recall they want the solution file, not the assemblies.
With the caveat being you have to be into that kind of thing. Coding C# not-in VS (or MonoDevelop) is not fun.