IAU tracks physical gold just like GLD, but at a lower 0.25% expense ratio versus GLD's 0.40%. Since both hold the identical underlying asset (gold), IAU is the more cost-efficient choice for long-term holding.

Its 23.1% one-year return has been nearly identical to GLD's 22.9%, with the same -23.8% max drawdown. For new gold ETF allocations, IAU is the more rational pick on cost grounds.