May I ask why you decided to reject potential customers to limititing it to only Visual studio users? What made you not create a stand alone application or eclipse plugin?
We decided to use Visual Studio for two very clear reasons:
1) Visual Studio has an enormous market share. There is growing interest in Ruby among Windows users (this was even before Microsoft announced its Iron Ruby project) and yet nobody was providing Ruby support in Visual Studio. That seemed to us to be a glaring hole in the market. The fact of the matter is that regular Visual Studio users on the whole don't want to switch to other IDEs. Ruby In Steel means they don't have to.
2) Visual Studio is, in our view, the most powerful IDE platform available. It is, in fact, more like an operating system than an IDE. Its API, SDK, automation model and tools are truly vast. This is something that few people appreciate, I think. In fact, you would really need to create a VS IDE to understand just what a world class platform Visual Studio provides to IDE developers.
I realise that many people like Eclipse and I accept that it too provides a very solid basis for the construction of an IDE. There are, of course, already several Ruby IDEs for Eclipse - notably RADRails, but also others including CodeGear's forthcoming Ruby IDE. This is not a market we wish to enter.
As for a standalone IDE. Microsoft's recent announcement of the Visual Studio Shell - a no-language version of Visual Studio into which other IDEs can be incorporated - means that this now looks like a real possibility for us in the near future. The Visual Studio Shell hasn't yet been released (it's due with Orcas beta 2) so we haven't yet decided how (or if) we will make use of it. In principle, this looks like a very interesting development, however.