Nolvadex has no bad sides that I know of.
Clomid is known to make you tempermental, moody, depressed (basically turns you into a woman) and gives some people acne. There are some other sides to Clomid too, I believe it's been associated with tumors (correct me if I'm wrong someone).
Some people claim taking Arimidex aids in fat-loss and incorporate it into their Clen and ECA stacks. Not sure if the same holds true for nolva.