I have a solution with 18 projects. I use user variables to control the path on the remote machine (it can change if I am compiling a branch) and the target host (I sometimes switch my compile host).
It would be nice to be able to define some user variables at the solution level so there would be one place to define them and they would be available to all projects and configurations. I right now have to automate this with a script, but it would be much more convenient to be able to use the GUI.