I've read the first book, and if that is as some have said the best in the series, then I would not be inclined to read the rest.
OTOH I've enjoyed the series and plan to watch the rest. AS for the merits of the books over the series there is a difference between a casual consumer and a fan.
In short, to answer the OP, there is no should. If you enjoy reading the books, read more, if not don't.