I thought I made a topic about it after I watched the first 3 seasons, but I guess not. Season 4 appeared on Netflix recently. Only 6 episodes long, so I guess the show creators fought for it just to have a conclusion, and I'm glad they did. They had to gloss over a lot of stuff that was clearly setting up multiple seasons worth of content, but the main character got her resolution, which is the most important thing.
I'd recommend watching it. Fun time travel series. Early on the story took a lot of influence from Occupy Wallstreet stuff, with the future being run completely by corporations. The future the show creates is nicely balanced too. When the show started everyone was saying how bad that future was, but it looked pretty nice. But as it goes on and more is shown you get a better idea what it's like. As the show goes on becomes less politically motivated and more sci-fi focused, but it's good all the way through.