My very first manual focus experience was with m4/3 earlier this year and though it was better after I bought an EVF, I still found it unreliable and frustrating (after 20 years using AF !). Then in early September I starred using a NEX with peaking, and I can say I've ditched AF since and am having a blast with MF !
Since I shot only moving targets (people and pets), magnification is useless to me, but peaking is godsent. I usually set it to Mid and use yellow in good light, and light in lower light.
What one needs is a LOT of practice, but you do get a lot better after a while.
So far AF performance in NEX (and I do have the new 6) hasn't made me want to give up MF.