I have the 831 (which is a newer version of the 830 without the BTX kit but otherwise the same case) and my brother has the Armor.The stacker isnt as big as it looks , it has only
9 drive bays so if you want to load it with drives have in mind that 3 of them are gone anyway using the HDD box with the 12cm fan.If you want another 12cm fan infront things get real tight.It still has plenty of room inside ,more than the Armor down and right of the mobo plus you can easily fit every PSU you want in it and you can manage your wires easily.Quality isnt all i expected since the Wavemaster i had before that was superb,but its still very solid and better than the Armor although you might have problems with the side panels and front door.
So having experience from both i can say 830 is well built in general and better than the Armor but you can put more fans in Armor (have you seen the side 25cm fan? ) and its cheaper.Both are good i guess but if i were to buy a case today i would get the original stacker