First season is great! Second season is great too (even though second season doesn't have things like showing same character in parallel universes which is what shown in trailer). But... third season just ruined the series for me. I felt it is very empty. After watching the full season I felt like I have wasted all my time. Time wastage in non required scenes, no new things; all such things have let the series down in third season. When I started watching this series I was expecting political drama in alternate world, alternate history, but I was left with some normal drama with non required romance.
If I had reviewed it after watching only first season I would have given 5/5 stars. But now only 1/5.