Probably airline redemptions, if you already collect with an airline where you will find the extra miles valueable.

Airline and hotel rewards are typically higher value than anything else because they're "excess capacity" awards. Gift cards, gas cards, and such tend to be all the same lower value, because the points are simply turned into money which Choice (or their parner) uses to buy the gift cards / gas cards at the same rate you'd buy them at a store. Thus once you get past hotel and airline redemptions, all the other redemptions tend to be exactly the same value, so then it just boils down to which ones you can actually use.