If you're thinking of building a Webapp with Node, it's hard to know which of these embryonic frameworks to pick -- or if you should even pick one -- since the laws of competition dictate we'll end up with one or two large ones.
This is a problem I ran into working with Merb -- spending time working with a framework, submitting patches, fixing problems, only to see it subsumed into Rails.
I'll still probably pick one to work with, since it'll likely be as round as any wheel I could invent myself. I'll be following the trajectories of these frameworks with some real interest.
node is indeed very interesting and has an unbelievable amount of mindshare in a very short amount of time. We are using node extensively at Joyent for system tools.
btw – kudos for sticking with pmpknpi ;)
I haven’t found something compelling enough to switch from pmpknpi yet—although eventually I might want to use something built on CouchDB.