I never finished The Americans but The Shield had the most perfect ending possible for that show and it was amazing! Worth checking out for anyone who has not already seen it.
FWIW I absolutely love The Shield, one of my favorite shows. The Americans is better. But it was also hard to get into, and I stopped a few episodes in the first time. It gets much better the more the story goes on.
As a fellow The Shield-lover, I highly recommend you try to finish The Americans.
