Heads-up...
In my test environment I found that SIM 7.5 wanted to uninstall my Mobile Management 7.2 SP1 installation in order to install ITMS 7.5. I had a quick chat with one of the ITMS product managers and have found that we'll need to wait for Mobile Management 7.5 to be released (scheduled for November '13) before I can upgrade my Symantec Management Platform.