It all depends on your risk profile and what you the investor want. You cannot say one is better than the other (fees excluded). NZ50 from smartshares will be more concentrated to lower cap stocks whilst the Simplicity one will have a greater range in its stocks. If you want accurate reflection of the index then the Simplicity one is for you. If you want the bigger stocks capped (meaning smaller stocks will be overweight) then the NZ50 from Smartshares is for you.