I went through creighton's EMT program just in the last year, and with any luck, will continue through paramedic starting in just a few months. As for the overall EMS program, it is hands down, the best in the area. However, I myself have looked into the MS EMS. All I can say about it is that if you have the time, patience, and money to do so, and you still want to, then go for it. Money wise, it is going to be expensive, as creighton is a private jesuit university, which i'm sure you already knew. Time wise, it's an extremely long process, as with any MS degree. Also in addition to all of the EMS classes, there are the standard english, math, history, etc classes you will have to take anywhere. Here is the kicker though: it is the previously mentioned jesuit university, where you will have to take many theology and religion classes, which will take over a year just by themselves. I have many friends who are undergrad students in other programs who must take these same classes, who say they are pure hell on the mind. If you're open to learning new things, then go for it. Otherwise, if you are a religious person and set in your ways (whatever they may be), word has it that they almost attack other religions and ideas in these classes.
On the flip side, encouraging you to go, there are many great things about it. Not only do you get the amazing paramedic course, but it is also essentially a degree in the entire field of emergency management, and they dive extremely deep into the entire field of EMS. There is a course taught by one of the EMS instructors on Medico-legal ethics and issues specifically in EMS, which seems like an amazing class to take, as we've gotten a snippet from the instructor in our EMT class.
With all that being said, if you have the time, money, and patience, do it. It is a great program from everything i've looked into and heard from instructors.