I went to Collision (Las Vegas) last year, and it was a waste of time and money.

Same startups, same VCs, same bloggers, etc, repeating the same stuff they said in a similar conference the week before i.e. loads of words are spoken, but no real content. Add to that the junk food they served, no seating (seriously, no seating through out the event for all the attendees), loud fans made it impossible to have a proper conversation, remote and random location, expensive, etc... and now the pay-to-pitch schemes. I felt treated like cattle. Stay away from these events.

The only tech event I strongly recommend attending is LAUNCH Festival by Jason Calacanis.