I'll be honest, I really bought this for a live version of Octavarium. In this sense, I was not disappointed. The entire first disc is extremely well performed as you'd expect from Dream Theater, with The Spirit Carries On in particular shining in a way I feel it didn't on the original album. The performance of Six Degrees of Inner Turbulence with the orchestra also had me excited, but this is where the album really falls down.
I know one track shouldn't affect an opinion drastically, but when that track is over 40 minutes long, it's hard for it to be a small complaint. DT are exemplary as always, but the orchestra? There are a couple of wrong notes in here (I've never heard this from a professional orchestra before!), and some of the strings section sound horribly out of tune with each other. HUGE disappointment here.
Every other track is good though, mainly because the orchestra seems to take a back-seat other than 6DOIT. Highly recommended despite that one shortcoming.