I once had problems updating from older madvr (mpc-hc crashing instantly), finally tried "reset to default settings.bat" and it solved the problem.
Smooth motion looks very nice, I have a 60Hz 30" 2560x1600 display and I don't notice judder anymore. I earlier used a terrible avisynth script which did some frame blending, but the results looked especially bad with checkered shirts and some other stuff. I saw no ghosting with smooth motion enabled, maybe it's there but it's nothing compared to what I had with the avisynth script.
Since I need to upscale all videos and original pixels are lost I didn't notice any sharpness difference between smooth motion on/off. But I will definitely keep it always on because movies are unwatchable with 3:2 pulldown.
About GPU usage, I have HD6970 and without smooth motion I get ~21%, with ~27%. So basically no difference with gpu usage (as long it's under 99% I suppose it makes no difference) but very much improved motion quality.
Thanks for the great update and keep up the good work
Edit: for the first time I looked at madvr's osd and noticed there's one fropped frame every 30.04 - 30.06s, so roughly 0,14% of frames get dropped. I don't know what causes this but at least that isn't visible while watching videos