There is a lot that is ridiculous about it, and it frequently had me shouting at the telly ("why didn't you get the bus half way, you tit?"), and also the influence of The Matrix has a lot to answer for. Green scrolly numbers? Long leather coats? An abundance of sunglasses? Does The Future *have* to look like that? Having said that, I did love the look of it, and there were just enough future-y stylistic bits without going over the top.
Philosophically it raised a lot of interesting questions (that it promptly ignored because hey, American blockbuster) and linguistically it had immense fun with the time-as-currency concept (even if the entire explanation for how things had got this way was dismissed in a one-liner at the start, which was essentially "meh, genetics").
Justin Timberlake was - passable? You got the impression pretty much anyone could have taken that role and done a better job, but he was okay (mostly I spent the film hoping he'd finally get rich enough to have a shave). Amanda Seyfried was fabulous, up to and including leaping out of a first floor window and running off in high heels. Cillian Murphy was good as the honest-but-law-bound cop (although did he have to spend the entire film chewing with his mouth open?).
And Alex. Oh, Alex. Can you please decline all future all-American hero starring roles and just spend your time playing English psychopaths? Because, yes. Please. Thank you.
...he's not actually in it all that much. Maybe five or six scenes? But Fortis is certainly one of the more interesting characters in the film. Shame we get less of his nasty wit and more of Timberlake's boring do-goodery, but there you go. I was always going to be rooting for him, wasn't I.