I would recommend waiting until S5 is out and doing 4 and 5 in a row. I never find the show anything less than enjoyable, but even I admit S4 was not a showcase for its strongest...anything. S5, however, is almost uniformly awesome, and it's setting a benchmark for using outside pressures (high cast turnover, returning from an "off" season, impending cancellation, lead pregnancy) as a means to improve a show.