Another vote for IB MAD T4S also the T4 (Schengen) lounge.
Both are large enough for a walk around to stretch legs/try different seating areas/styles, views, staff, bars, range of food/nibbles, are all good.
They are long lounges, if you've time, start your visit by exploring otherwise you may not see all the different food/drink available.
The showers are very good, they put BA's at T5 to shame.