First this discussion does not include Iron Clan Machined Plate but only ordinary machined plates. Pros: It gives good proteciton and it adds to strength so that you can use that weapon you lack ST for w/o penalties. Cons: Well it does weigh 1000Stone while adding only 3ST so when you're a low ST character and put it on you're sure to get at least moderate encumbrance and speed loss as a consequence. Also there's this huge noise penalty. All in all I do equip my team with this armors but it really pays off only in case of characters with ST13 and up.