Medium: Good chest defense 51 pts in body armor when loomed, bad head and legs, overall, having 2 weaknesses may force your enemy to aim for a certain spot over another which may offer you an unorthodox advantage, if he aims for your torso, you are well protected and you have earned your speed and agility bonuses to overcome him. I highly recommend this build for the standard saracen infantryman or archer.
Medium: Better head coverage here, decent, except for the odd stray arrow to the knee.
Medium/Heavy: The negatives outweigh the positive benefits on this one, as it weighs considerably more but only offers +4 pts in body armor.
Heavy Lancer: This combination offers great leg protection which is important when mounted, good body protection against arrows and head protection. Drawbacks may be the slowness upon dismounting but depending on your build you're still faster than anyone in plate.