I'm guessing most (all?) the developers you know work in the US?
Mac OS is close to nonexistent in that area in the rest of the world.
Trying to sell an app competing against a free product from Google is already challenging enough, you should seriously consider the original advice and extend your tool to work on Windows as well.
> Mac OS is close to nonexistent in that area in the rest
> of the world.
I'm fortunate to be working for a consultancy company that just gives everyone a budget to buy their computer. Most people have a Macbook, with the odd exception that simply has a hatred for Apple or can't get used to it.
I would argue that development tools are much better for OSX. It's like Linux, but usable. A lot of commandline tools just work out of the box under OSX, where you have to go through hoops, hope there's a port, or install a bash emulator under Windows.
Of course, .NET developers will be using Windows.
And this is a two year old observation.