Yesterday, I fired a Virtual Machine with Visual Studio 2015 RC. This is the best way to try out this. Unless you need to download the installation files and install them. I think it requires about an hour, firing a VM is only about 3 minutes.
I tried it for a little while, that is not bad at all. The major improvements are in mobile app development, it has a better integration with xamarin. However, you still need to download xamarin.