Peaking definitely does help. I always found manual focus on my GF-1 to be difficult, but on the NEX it is much more enjoyable. I've long been looking for a Summicron-C or Minolta M-Rokkor 40mm. I think they would be fantastic lenses on the NEX. However, they seem to have gotten pricey and at the current price they are going for, I would have to consider the Voigtlander 40mm as an alternative. But, since you have already have the Summicron, put it on your NEX and I think you'll be pleasantly surprised.
