This series keeps you on your toes the whole time, well-paced engaging story, well fleshed out characters played by very good actors (great chemistry between the leads) and narrative that is well planned out as well.
If you watch it the second time you can also judge how well certain parts play out when you know the ending. It must be said tho that avoiding spoilers is necessary to enjoy this show the most during the first watch, it keeps you guessing and fully engaged until the end.
Female lead is the one that shines the most for me here.