which javascript library?

Once I got into doing more javascript work, the less I found myself using the rails javascript helpers and rjs. Most of the time I end up with half of the amount of code in less time not using the rails helpers and rjs. So now I've been looking around comparing prototype/scriptaculous to other frameworks. So far I'm leaning towards JQuery. It's documentation is probably the main reason, and it has an object oriented approach similar to prototype. I also looked at YUI and Mochikit, but in the end did not like the more functional style that they used.

So to all the javascript experts out there, is it largely a matter of taste, or are there other reasons to choose one javascript framework over the other? I've seen a number of debates over how some frameworks use namespaces, but that's about all I could find as to the real merits of one versus another.