It was okay. Not at all the must buy I had hoped for and felt, at times, it was more like a warped history lesson than an exciting book. It was nice seeing all the characters in different roles and the art was nice however, so it was not a flop by any means, just didn't wow me either. I would certainly rank it in the "You should at least borrow it to read it" category. It was no EARTH-X for sure.
The follow ups - I only tried the first issue of ... one of them and I just wasn't into it, so I can't honestly speak on the entirety of them.
Depending on what you are paying, I wouldn't pay a lot for any of them, I would stick with the main book first and then decide (unless you are getting a bargain for all three)