The easiest way to get stats changes besides having it in the pedia is to just go in the soldier page for a gal wearing an armor with no mod, then equipping the armor. You will see the changes immediabely (the inner color moves, but not the outer, darker one, and the numbers change).
You can indeed see armor values when in battle mode as well, but resistances do have to be guessed at.
The ship you raided contains "midgame" armors, and can be a boon if found in the early game (like in Meridian's LP). I am quite annoyed it spawned on a different continent when it popped in my game. It is not the normal way to acquire armor though. You can get one upgrade for tac vests and a pretty useful variant quite easily, then yes, interrogations, analyzing loot and some weapon analysis can be helpful.
