I attended in 2011 and made it to the semifinals of LCQs. I lost to the dumbest thing ever, I didn't think a -1 Tornadus with an Acrobatics Flying Gem could kill a 252 HP Scrafty. And I had Protect. Oops.
The Pokemon store was ok, the line was long and most of the cool things were sold out. It only sold Worlds-specific merch so I got a T-shirt and a binder.
No. D: I've never really even seen any streams. Thinking of changing that this year, as a huge Pokémon fan I want to experience as much of this as I can.
I've never managed to make it to Worlds as either a spectator or as a participant. I eventually would like to change that, however.