What we've got here is the entire ELO studio album discography between On the Third Day and Time, minus the best sellers Eldorado and Out of the Blue. As is typical for this series, albums that still sell reasonably well on their own are excluded from the "original album classics" box.
Each album is represented by the most recent mastering and each has bonus tracks. The bonus tracks are hit and miss, but the albums sound good and if you're an ELO fan, you will want them all, so this is a good and cheap way to get them. They come in mini sleeves: Cheap quality reproductions of the original covers, no inner sleeves, no liner notes, no gatefold for Discovery. But it's really about the music, right?
As for the music: Four of these five albums are classics: On the Third Day, Face the Music, New World Record and Time. The only weak link here is Discovery, which is a bit too slick and with a weaker collection of songs. It's not terrible, just not up to the standards of the other four. That said, any fan of ELO will absolutely want all five.
This is highly produced, Beatles influenced pop music with a lot of orchestral (or on Time synth) embellishment. No one did it better than Jeff Lynne/ELO at the time. I'm not sure anyone has done it better since.