I have already answered about VS in a comment.
In terms of .NET interoperability, IronScheme is probably better, due to being designed and written in .NET and liberal reuse of existing .NET types.
In terms of being a .NET consumer, IronScheme provides excellent support for most .NET features (eg generics etc).
In terms of being a .NET producer, IronScheme still lacks a bit. Example, cannot create generic methods or classes. Typed fields (on records) were only recently introduced and even that is a bit limiting (no support for mutual recursive field type definitions).
Example what a mean by above:
class Foo { Bar bar; }
class Bar { Foo foo; }
To produce something like this, is not possible currently, but something that is doable (to some extent).
With some developments towards the end of last year (2011), I have made it possible to write code in IronScheme that runs as fast (or even faster) than that in C#. The method IL output of the code matches F#'s closely (by pure coincidence). I dont even bother benching against IronPython/IronRuby anymore. :)
Feel free to ask more, if needed.
Also, there might be some informative discussions on the Codeplex discussion board for IronScheme. I normally respond very quickly.