IMO Cmake's "killer app" is that it will generate projects for Visual Studio and Xcode, which allows you to get access to the Windows/Mac specific tooling that those products offer. It's also a LOT faster on Windows than Autotools because of how NTFS performs poorly when dealing with writing a ton of small files. I agree that its syntax is ugly but once I got beyond that I found it fairly simple to work with. The most annoying part was figuring out which MSVC flags corresponded with the GCC flags I use.

Out of curiosity, what does your C++ development workflow look like? Do you stick to using a text editor rather than an IDE?