What are the best tech conferences you attend?

LibertyJS in Philadelphia--great to meet lots of local tech people, and learn a lot about various aspects of JavaScript, which is an area that I'm trying to grow in.

Craft in Budapest--fantastic collection of speakers from all parts of the world, non-platform specific, great workshops, and a beautiful backdrop!

Such a great question, Lorenzo! Surprised to see that there are no replies on this yet.

I am trying to attend conferences related to the technologies I work with, ie: MuleSoft, Amazon WebServices and also local conferences (in my case Stockholm) that are known for good quality content, speakers and with that talks (example: Nordic APIs).
If anyone wants to know more details, I'm happy to elaborate.

To answer your other three questions:

• Q: Where are they held? A: The conferences I mentioned above take place in Stockholm, Sweden
• Q: What makes them the best? A: This is a tough question to answer to. It's difficult to rate a conference as "the best". There could be years when they are very good and years when they are not quite up to the expectations. Overall, I like to attend these because they cover topics I am interested in. And knowing some of the speakers plus the agenda helps me make a good initial impression.
• Q: What do you like about them? A: Both the talks and networking with other professionals in exchange of ideas.

If you're a newbie, codelandconf.com is an absolute must

CodeMash - Sandusky, Oh
It has 2 days (called pre-compiler) of 1/2 to full day hands on training courses and 2 more days of conference speakers.
I learn so much on all facets of development and love talking to other passionate developers.

NCDevCon - Raleigh, North Carolina. It's a weekend conference covering HTML5, JavaScript, TypeScript, web, mobile and ColdFusion development. It's very relaxed, and is held at the NC State University campus. It's a great opportunity to learn at a reasonable price. It also happens to be this weekend (October 7 & 8).