Steel vs. Ceramic
Ceramic is generally lighter than steel, but this is not always true; I have seen ceramic plates weigh over 8lb. Ceramic is molded and is easily formed into very ergonomic shapes, but this is not always true; some are just plain flat. Level III Ceramic is designed to take 6 hits. Ceramic usually costs much more than steel. Ceramic is designed to break. Small tiles explode when impacted by bullets, but a second hit in the same spot is deadly.
(This Level IV ceramic plate was hit with only 4 FMJ .308 rounds. The 3rd round penetrated.)
Steel plates are generally heavier than ceramic, but this is not always true, ours weighs ~7.5lbs (plus 1.5lb for the coating). Our hardened AR500 steel is cold rolled, laser cut, and then bent to a 20 degree bend that fits most torsos. Infidel Body Armor can take more than 100 hits from common military rounds. Our steel armor is very economical.
The downfall of most steel body armor is that when a bullet strikes it, it fragments. This causes hundreds of projectiles to explode though the air, possibly injuring the wearer and those around him. HOWEVER, Infidel Body Armor is coated with an Anti-Spall Coating that minimizes spalling and bullet fragmentation. Check out the slow motion video here for proof.