Here's my review of Pilot's Waverly nib:
Like the Pilot Posting nib, I think the Waverly is a fantastic yet under-rated and under-discussed nib. Though it's not quite as fine as the Posting nib (which I find to be just as fine as my Pilot Falcon/Elabo soft EF), it's even smoother. It's designed to write on crappy, rough, bumpy paper (although the question is, why? :-) ), and I've therefore found it useful when drawing on cold press watercolor paper. But it's also a dream on ordinary smooth paper!