After using Prototype for the past 3 years, I've decided to check out jQuery a little more. I first heard about jQuery around a year and a half ago, but didn't spend too much time working with it since Prototype had everything I needed. After reading how everyone gushes over jQuery, I figured I should give it another shot, at least for comparison sake.
After first pass, it seems pretty powerful. The markup is a little foreign at first compared to Prototype. I'm not saying it's better or worse, just different. The selectors are much better in jQuery, which might be reason enough to convert. I haven't worked with Ajax in jQuery yet, but from what I've read the syntax appears pretty simple. Granted the syntax in Prototype is pretty simple too, so that's not such a big deal.
The biggest pain transition is going to be adjusting to the new $ method, which now returns an array of jQuery objects. Not exactly looking forward to the confusion.