First off: All the negative reviews that appear here aren't related to the music that's here. They are related to the fact that this was misleadingly marketed as the soundtrack to the reformed ELP's shows at the High Voltage festival. It's not. It's just a compilation of old studio material.
OK, now you know.
What do you get?
1) Side one of Tarkus in its entirety. (This is the 20+ minute progressive suite that stands proudly as one of the best extended pieces of the genre). 2) You get the entirety of the live Pictures at an Exhibition album. 3) You get about 1/2 of their debut album, including the best tracks, and including the 12+ minute extended opus from that album, Take a Pebble. 4) You get one of the two group showpieces from the Works Vol 1 album, Fanfare for the Common Man 5) You get the minor late-era hit Touch and Go
That's it. And taken just in terms of music, that's a pretty good list. Strangely, you get absolutely nothing from their biggest album, Brain Salad Surgery. But side one of Tarkus and all of Pictures, plus the three tracks from the debut album constitute something of a generous best-of of the first three albums. Combine this with a cheap copy of Brain Salad Surgery and you'll have a pretty good cheap starter collection--although you'll have nothing from the worthy Trilogy.