The last time I looked into Zepto (which, in full disclosure, was about a year ago), there was a gigantic HN thread with many people (including John Resig) complaining that it being "JQuery-compatible" was more about syntactic sugar (functions whose signatures look like those in JQuery, but don't behave the same) and marketing buzzwords (comparing it to JQuery obviously attracts attention) than actual feature parity. Has it improved at all?
I've been using zepto in a project for a couple of months and so far it's been pretty solid. It's true that it does not achieve feature parity with jQuery, but it doesn't pretend to (and I don't think it ever did). It does successfully mimic much of jQuery's core functionality on Webkit browsers at a fraction of the file-size.
