It's a tough situation. We know that Frank recorded literally everything, and we know that there have to be many hidden treasures. But when it's anyone other than Frank putting the tracks together and doing the liner notes, I still feel like it's not a "real" Zappa/Mothers album. And yet, this is the best we're gonna get now that he's gone.
I'm not one of those who loves to dig into 500 different live versions of the same songs, so in any one of those later releases, there's maybe 50% stuff I don't really care about. I rarely find myself preferring a live version of a song, even a really good live version, over the studio version I've been listening to for 30 years. Usually it's somewhat interesting, amusing at best. Frank loved to play with the arrangements, so there will be parts sped up, parts missing, extra stuff injected, and overall it usually just sounds "wrong" to me. I'm sure that most people aren't as anal as I am, but I'm probably not alone in feeling that way either.