You are probably like me; you already have various Yes albums, including Yessongs. Think of this as the newer version of Yessongs.
You get four CDs worth of live music, but unlike the CD version no DVD of the performance.
If you had the DVD, you'd have seen that the venue was, by Yes standards, very small and intimate. This definitely colours the music and, from my point of view, makes it far more personal. I like it.
The other things that mst be said is that this album is excellent value - when I placed my pre-order, my thought was that I couldn't possibly lose at the price and having now listened to the album, I know it was money well spent.
So, if you are a Yes fan, then you probably already have all these tracks, but maybe not the intimate mix. So buy it.
If you are new to Yes, and you already like prog rock, then this is a great starter. However, I doubt there are many prog rock fans who don't already know Yes.
Oh, go on, just buy it; you know you want to!