I actually went to the Glee Live concert in London on the 26th June 2011 and words cannot describe how fantastic it is. It obviously doesn't have the real experience rolled into a DVD because being there was fantastic but it's pretty close.
If you love Glee, then you'll love this. It's a movie of the concert, with all my favourite songs. It also has some backstage peeks that you couldn't have experienced throughout the concert. Not only that, but it has a couple interviews of people with real life situations and it describes how Glee has changed their lives. How it's helped.
If your thinking of buying this for yourself or for somebody else who's passionate about Glee, I say go for it. It won't disappoint you. You'll find yourself re-watching it. I wish I could travel back to the concert, but i'll always have this DVD to look back on for the memories.