Raw first video from the 550d on my Droidworx XM x4 copter. It felt heavy just carrying it from the van, but one in the air the weight didn't seem to be an issue. I have lots of work to do on gain setting for the WKM and trimming the gimbal but the picture quality from the canon is so much better than my GoPro Black!!
I am very relieved that the whole effort of building the XM is going to be worthwhile - it was quite an expensive way of flying a GoPro after all but the additional weight carrying capacity of the octo made the 6.7kg (total) lift look easy.