One thing that I'd add is that I have found a clear line of differentiation between the open and closed source FCs. They all have their pros and cons; whether it be price, flight characteristics, or ease of use or features.
What I've found in my experience is that the open source will take a bit more time (or possibly a lot more time) to achieve the flight characteristics and functionality that is often found out of the box with closed source FCs. For some, the research, learning and tweaking required to get a multiwii flying great will be half the fun. But for some it's a frustration that prevents them from continuing to grow in the hobby.
And in my experience, closed source may not have all the features packed into the open source boards. For some, the price of a closed source FC that doesn't have the bells and whistles of say a Pixhawk, will be a turnoff, and make someone feel they wasted money.
I think it's important to ask yourself which type of person you are. This way, you won't be disappointed by the time it takes to get an open source quad in the air flying well. Or you won't be pissed you spent $300 for an FC without waypoints.