theoretically it may affect your credit scores; however, in my experience, it does not make a big difference. I've canceled a couple of credit cards, when I apply a mortgage, I still got a good rate.
% U4 M7 W9 Q1 o" F( Q. {but compared with other rewards cards, the rate of getting points is not good enough. But if you buy things a lot at their stores, it is very good.