I thought it was OK. Never watched any of the shows outside of Crisis ... at least not since Smallville (which I saw most of). Most of the really good stuff was the fan-service cameos, though. Routh's Superman stole the show, and Conroy's Bruce Wayne was phenomenal -- I'd watch a series about that guy. I didn't mind the Smallville twist ... thought it fit his version of Clark well. The Green Lantern, JL Flash, etc. stuff was cool.
The plot itself was mediocre, though. The fight scenes were fairly mundane. Tyler whats-his-name is not a great Superman. Green Arrow was the best character of the regulars. I'm willing to overlook some stuff not making much sense, figuring it would've made more sense had I actually watched any of the preceding shows. But, it was like somebody with at least some competence sketched the plot ... and then handed it off to a teenaged girl to write the dialogue. Seriously terrible dialogue writing.
And, what in the world was with the giant plush teddy bear attack? I'm guessing that was a callback to something in the history of one of these series ... but it was stupid.
After all of that change in the world that they wrote-in due to the Crisis, why wasn't the Presidential address delivered by President Lex rather than that Meredith Viera look-alike? Would've been a much cooler ending, and set-up a cool conflict going forward for Supergirl (I'm guessing Lex is from her show).
There was some good stuff mixed in there. But, I didn't love it.
SnakeDoc