There's no issue with the fidelity of the recordings, to my untrained ears. They sound fine.
It's a nice box for what it is -- a generous sampling (over 80 tracks) presented in an orderly, chronological fashion, and accompanied by a very nice booklet.
Just to elaborate on the packaging, the individual discs (at least in my copy) come in those cardboard slips, not jewel cases. It doesn't bother me but you just need to be a little careful in handling them.
Sounds like I'm sold on the set. Great value for the money. As for the cardboard slips, really not a big deal to me. I own a 33 disc Haydn symphony cycle with cardboard slips.