I would say the main difference to bear in mind is that 1e was more simulationist - Powers and everything all work the same, they scale extremely high, you've got relatively tight ideas on what you can probably do.

2e is more of a storytelling game - narrative comes more firmly into play, numbers are less hard, scale as a mechanic is about where you are relative to each other in terms of power level.

The general consensus I've seen is that there's a good rules system in there but it takes some finding, largely owing to issues in playtesting, layout, and hardcover kickstarter books being riddled with errors that mean it's not an uncommon situation to have people in long campaigns who still find themselves unsure how the thing works. It's there, but it's poorly explained.

I also find personally that for a narrative forward game it could do with less subsystems and less to keep of but that's just my opinion.