Something I noticed about spreads. A UK or European brokerage often has a smaller spread on the EUR/GBP than a US broker. So, I guess an Australian or New Zeeland based brokerage could have a significantly smaller spread on the AUD/NZD than brokers elsewhere.
Beware of super-small fixed spreads. The broker is not in this game to lose money. If they can't cover the official spreads, they'll likely get you through slippage and requotes.