There are times it was slower than one might expect of this type of show, but mostly, I loved that it was that way because you had really great character buildup. You really get to know the characters and feel their emotions and perspectives.
So, if you are looking only for a highly intense non-stop ridiculously impossible action packed show to watch, then skip this - it's too intelligent for you. However, there were certainly very cool action scenes throughout it and I was not disappointed at all. Looking forward to Invasion 2.