I'm committed to a new 6" just as soon as my friendly gun shop gets one in (they currently have a 4" tempting me daily) - I'm next in the queue. I like the 6" sight picture better and the weight and feel is similar to many of the 617's bigger bore siblings. The 4" is super nice, and I'd definitely keep it if I had one while pursuing the the longer barrel version.
In the end, if someone absolutely must have the best 22LR wheel gun today, then all the research and anecdotal evidence I've been through in the past month suggests that there's none better than 617PC.
Happy trails,