To be honest Chaos Cloak wins easily, they are practically the same except chaos cloak gains a weakness to the second least present status in the game (curse) for universal CTR and ATK boost.
However, the Mad bomber does have one tiny little advantage. To state what may not be obvious the Mad Bomber set is obvious. If you see a player in a Mad bomber set it is obvious what they will do... they bomb, and with a Glass "bomber" suit like that they probably do it well. (of course if you see one using just guns and swords then you have yourself an idiot or someone with no other elementally resistant armor)
Chaos cloak on the other hand well you don't know what to expect from the person using it (anything could happen).
I'm not making an argument for a reason to craft a mad bomber set (short of having an awesome costume) I'm merely trying to see a little bit of light in this rarely used armor set)
When Chaos was buffed, this was a hot topic of discussion --- that Chaos made Mad Bomber obsolete. Mad Bomber does look great, though. Especially with the mohawk.
It's not so much a clear indication of a good bomber, as a clear indication of an old bomber. Everyone I know with Mad Bomber crafted it before the Chaos buff.