We use Visual Studio 2015 for current development. The vast majority of the code is in C#, with a small portion in C++. You can use the community or free version that MS provides, or any of the higher paid versions.
There are a couple settings that need to be configured in Visual Studio so your code formatting will adhere to our preferred style.
We also have access to some very powerful tools courtesy of some of our partners who support open source projects. One very powerful tool is Resharper. If you are an active developer and are interested in using this tool contact us on the developer list and we can discuss getting you one of our team licenses.