The metal armor will keep you alive longer versus bullets, since while the two armors will have similar damage threshold, the metal armor will have higher damage resistance to protect against aimed shots. The metal armor will also protect better against energy weapons and grenades due to providing energy (and possibly heat) resistance.
The riot gear will keep you alive longer versus melee attacks as it has similar damage resistance and threshold against mechanical melee damage compared to the metal armor, but, also has a chance to block melee damage.
Based on the stats you posted, I assume you are early in your playthrough, so the metal armor may have significantly higher armor penalty than the riot gear. If you rely heavily on mobility or stealth, and aren't regularly dying to bullets, I would recommend the riot gear. But it all depends on your build and where you are at in the game.
