I really loved this, as a fan of most or all of the characters involved.  I was pleasantly surprised that it delved into a little more info on the Flashpoint universe--I thought this was just another so here's what these characters are like in Flashpoint issues, but I loved the map of the mostly sunken Europe.  I especially enjoyed the presentation of Dr. Fate, who is apparently another that knows that history has changed...that makes at least 3: Flash, Booster Gold, and now Dr. Fate.  (Who else, that I haven't read yet?)

More than anything, though, I thought the artwork was top notch.  I would love to have some of those full page splashes of Deadman and the Graysons flying around in the big top hanging on my wall!