I need to order some. I have been torn between wanting to stock up and wanting to try the 4s.
I just got some pure cadence 4s and it looks like the updates they made to that shoe are very similar to the updates they made to the pure flow.
I've run in them a few times now and I have to say I really really like the bigger toe box. the shoe feels lighter to me than the 3s, and I like the heel better. It seems to really hug my narrow ankle, but gives plenty of room for my toes.
PC3s are less than $80 now on their site. I'm not sure i like the 4s that much more than the 3s, so I think I'll keep the 4s that I got to try out, but stock up on clearance 3s.
But I do like the 4s, so wont be bummed when I run out of miles on the 3s.