He will put an end to Gotham's suffering, once and for all, no matter who he has to go through...
BATMAN, THE GOTHAM KNIGHT
VERSUS
JACK HAWKSMOOR, THE KING OF CITIES...
Second Printers, YOU DECIDE...

'Cause I'm old, I remember Armageddon: 2001, DC's 1991 annual event, the first to take place entirely across their Annuals rather than interrupting their monthly titles. Genius that, I say, the idea of running an event through Annuals, not necessarily the Armageddon series. Armageddon: 2001 had two bookend issues between which all the other annuals appeared, and each annual was, by and large, a stand-alone excuse to tell an out-of-continuity story set 10 years in the future about the characters and teams holding their own titles. The Plot? A character named Waverider was checking every superhero to see who would possibly become the world-conquering Monarch, and in a famous pre-internet spoiler foil, DC changed the big reveal from Captain Atom to Hawk (of "& Dove"), something which kind of pissed off a lot of people (especially after Hawk had already been ruled out in the H&D annual). Superman had three or four different futures, which just went to show that you couldn't really trust or believe anything you read in the other issues.
The mid-1990's, at the apex (or perhaps just past the turning point) of the comics boom, spewed forth the Amalgam Universe, where DC and Marvel heroes smashed together in puntastic ways for two series of one-shots. Then in the late-1990s DC had the "skip-week" events. To explain, every month consists of four weeks, but every three months there's kind of an "extra" week on the schedule which DC used at the time to have self-contained mini-series or mini-events. One skip week brought forth the "Tangent Universe", a new bundle of heroes in a shared universe with familiar names and not at all else. Both the Amalgam and Tangent Universes had solid creative teams, but investment in the characters was low (since they were essentially one-off creations) and thus so was enjoyment (even though the Tangent universe has reared its head a couple times since).
I've seen this before, multiple times, and the potential for fun is there as it always is in alternate past/future stories. But at the same time the sprawl of Flashpoint, with over 15 titles per month (Booster Gold, I might add, is the only current ongoing series tying in) means it's not going to be a cohesive story, and knowing what's the meat and what's just fat is hard to tell from the outside. Even at a "drawing the line" price of $2.99, that's still around $50 monthly to buy into the event in total, so as a fan, if you're curious, what do you do?
I should also mention that I've been avoiding the Flash since the return of Barry Allen so I've had zero build-up to this event, and I have to wonder if this event is catering to anyone outside of the Flash readership. Obviously it is trying to considering the diversity of characters and titles involved, but will any reader who hasn't been keeping up with the Flash have a vested interest in the series especially if they can keep reading their regular monthlies without interruption?