I went to the World Youth Day in Madrid

. Most people say statements such as “I had a blast”, or “I had a really good time”, because it’s really difficult to express in words exactly just how awesome the event was. You could almost get a taste of Heaven being at the World Youth Day in Madrid, Spain.
I second LDNCatholic’s point that it’s best to go with your diocese. It simplifies the process a lot more. Looking back, I’m quite happy I went with my diocese rather than as an individual pilgrim. Going with your diocese doesn’t hamper your freedom too much - they generally give you free days, free time, etc, as they acknowledge that adults are following them. But they do expect you to attend early Morning prayer, evening prayer, and a few other essential activities (but these are few and far between compared to the freedom you have).
As for comments concerning pilgrims unable to find a space at the Cuatro Vientos airfield, that’s sadly true. It never happened to me (I was very lucky), but most of my group had to sit in an area further from the Pope that was not even allocated to them in the first instance. They also received their lunch packs extraordinarily late, and upon receiving it, had to share the little leftovers they received. The state of the portable toilets was also absolutely abysmal that it sickens me thinking about it.
But I think, on the whole, the 2011 World Youth Day was a success. You have to take things into perspective: Roughly 2 million people journeyed to see the Pope, and it was peaceful. In London, the Nottinghill Carnival got far less people: there was a stabbing (caught on camera, I might add) and some drug dealers were arrested.
I’m not sure if 2013 WYD will live up to what happened in 2011, but I guess you’ll have to see for yourself
I loved it.