When you consider imaging track, your job perspective is much wider. For example, I've been working at MR lab here at UCSD. UCSD has no medical physics program, but we have MR Institute for research. Quiet well-known in MR community. Most of people I met from here went on and are now very successful. They found jobs from all over ranging from psychology department to General Electric. MRI research is not just about making scanning and data acquisition time faster. It has very reach goals and many of them are shown to be promising. For example, recently, researchers has developed an MR sequence that can image bones and skeletal structures. This is amazing! I've seen these technology with my own eyes and attended seminar. This is not just due to pure programming and signal processing work. This type of research is fundamentally challenging that one has know lots of physics of spin and r.f. property of materials and so on. And don't forget the ever increasing clinical application of fMRI.
As for me, I have no preference yet. But one thing is clear, I am going to chose research that will allow me to build many skills that can be applied to many different disciplines. For example, if I go on to do imaging track, I want to do MRI and its pulse sequence design rather than hardware. That way, I can be valuable to clinical type , chemistry, physics, psychology research group. If I go on to do therapy track, I would join a group where I can learn monte-carlo simulation of radiation transport the most and it is pretty obvious why.
I don't know why I wrote what I wrote here. I guess I was little challenged by hearing that MR research is same everywhere and boring (okay, you didn't say boring but....).
And about UWM invitation day, I miss understood you. I'm pretty sure it's all paid for it. That makes much more sense~