argonauta, not to really cause an argument, but have you ever used jQuery?

Code formatting depends on the person writing the code. Yes, things can be chained together and in "one line". But that one line, can be neatened up and broken up across lines. Most programming languages and other libraries can be written in a messy way. It's all in the user.

Selectors in jQuery are extremely fast. So far that it's basically irrelevant.

Any plugin is written in it's own namespace. They won't conflict with other libraries.

And jQuery is ~19k.