Dude get a bgs zgs is just a waste of money. Totally useless spec unless ur going to be fightning in castlewars, pvp, or Bounty hunter. (Some people in Bounty Hunter also use this weapon very effectively, as any opponent without brews will realise: it's difficult to win if your defence and strength have been lowered hugely.)
Bgs spec (WarStrike,) can do a lot more damage than the zgs spec (Ice Barriage.) It can lower ranges of stats as: Defence, Strength, Prayer, Attack, Magic, Ranged. Also An extra 10 percent is added to the inflicted damage. So it makes the bgs a relatively good choice. Also its general popularity for godwars.
Because General Graardor is the most popular boss to kill in the God Wars Dungeon, the Bandos Godsword is the most useful choice of gs when fighting him.
So lets get it straight, all in all the bgs is a good gs. Not neccessarily if your comparing it to an sgs or ags but good enough for taking out enemies. Its worth the money.
Get yourself a bgs.
-There will be blood shed