Here's the way we look at it. We're on vacation, it's not like we have the opportunity to visit WDW every month so we tend to save a little extra when we are not at WDW so we can spend it there.
If you can manage the extra $, I'd try and do both. If time is a problem I would chose the one that is less frequently available. That would lead me to advise you to go to MVMCP.
Cirque is there year round except for 2 or 3 weeks when they take a break. You can check out their website to find out when that is.
We are doing both this vacation so I'll let you know which we enjoyed more when we get back.