jQuery is a much smaller scope than Prototype or Mootools -- it doesn't try and enforce a JavaScript framework.  I previously avoided it because it provided so much less general programming tools than the alternatives.<p>However, in the years since I made some of those technology decisions, jQuery has become the leader and thus more and more 3rd party technologies have been built around it.<p>I've recently switched to jQuery from mootools but I had to seek out a lot of plugins and other libraries (and build some stuff myself) to reach the same levels of capability but ultimately I'm happy with the results.