Referred to as FCs, you need one of these to make these medusas work. And as luck would have it, there are a gazillion of them from which to choose. I have personal experience with two of the most popular – at least at this point in time of 08/17/13. Those are the NAZA M and the KK2.
My experiences with both are as similar as they are different. On the one end of the spectrum is the KK2, available for less than $30 thru Hobby King and various outlets on eBay. The first one I ordered from HK, I worked with for about a two weeks before discovering it was bad. Fed up with that experience and flush with cash, i went to the other end of the spectrum and bought a NAZA M. Available from multiple stores, I bought mine from a local hobby store (LHS), Experience RC for the going rate of $299. The manufacturers call it “unilateral pricing.” I call it “price fixing.” Regardless, after a couple of hours with the NAZA, I discovered that it too was bad. So there is no guarantee, based on price, that you’re gonna get what you pay for.
Because I purchased it from a very reputable LHS, I was able to return it with ZERO problems — yet another advantage to purchasing from a real brick and mortar outfit.
The other board which I have no experience with is the CRIOS All-in-one board. So I will have to defer to what I have read and to others experiences with it in my posts.
Take a look at the detailed descriptions of each of the boards to find out the advantages and disadvantages of each.