I've worked on a big tablet-first site where we first built everything using Zepto, because of the assumption that 'everything would work the same as jQuery, bu

I've worked on a big tablet-first site where we first built everything using Zepto, because of the assumption that 'everything would work the same as jQuery, but it's smaller and faster'. Unfortunately, we encountered a lot of bugs, inconsistencies with the jQuery API and general lack of interest in supporting IE. Somewhere halfway through the project we switched to jQuery and we didn't have any performance problems. Some things actually worked better because jQuery has better workarounds for some of the bugs in older Android browsers.