SDK 4.0 & Visual Studio

Just installed the preview of the CIQ SDK 4.0.

Most of us probably don't look at the SDK release folder, but there are some pretty useful HTML reference docs in there. Core Topics is a particularly nice refresher.

I also see that Visual Studio starting to get more serious support. I've only ever used Eclipse. I understand VS is going to be a better experience for developing CIQ. If it is like Eclipse, are there different VS packages? If so, any guidance on which is the best download for just working on CIQ stuff? And it is totally free, like Eclipse, right? Thanks!