I usually use whenever I go do champs, peerless or DF's
Has it made or broke any fights?
Think of it this way, its like a fighter char wearing a normal 70's suit with no bonuses over wearing a 70's suit with decent bonuses ie HCI,DCI,etc
The better suit may keep you alive easier and it defenitly helps but its not a game stopper if you dont have but if you do have why not use it.