I own the 50mm f1.2 L and the 85mm f1.2 L. Both lenses are awesome, but it's always hard to nail perfect focus at f1.2 due to the autofocus not being 100% accurate 100% of the time.
Focus errors are more noticeable at wider apertures due to extremely shallow depth of field. The closer you get to your subject, the more tricky focus becomes. This is when afma (autofocus micro adjustment) is useful at a set shooting distance.
Personally, and if possible, i always shoot three similar pics with the f1.2 when using wide apertures. The af on your camera will undoubtably be more accurate and consistent than manual focus using viewfinder (without live view magnification) as the human eye is not always perfect either. The Otus is no doubt a great lens but i bet nailing perfect focus every time is a b*tch without extra special care and a soft pic is useless even with a sharp lens !
I love the 50mm f1.2 so suggest you try it. If not, i think the 50mm f2 (?) IS will be out this year.