As the person at Sonatype responsible for marketing and channels, my team and I frequently sponsor, attend, and speak at a wide variety of technology conferences.
Over the years, we've learned first hand that not all of them are created equal. Turth be told, there are infinite options to choose from, and it's difficult to determine which ones are worthwhile, and which ones are not.
In that sense, technology conferences are quite similar to open source software components. There is an infinite volume and variety of options; but identifying the ones that will add the most value to your business is tricky.