Oracle of Seasons is better, but both games are worse than Link's Awakening, because they are more "complicated".
In Oracle of Ages, there are two overworlds with large maps (Past & Present), kinda like ALttP's Light & Dark World. In ALttP, you can explore a majority of the Light World before even going to the Dark World. Unreachable places can be reached later from the Dark World by using the Magic Mirror. In OoA, you will go to the past rather early in the game. Unlike "finishing" the Light World by exploring the Dark World, switching the time period in Ages makes the exploration more difficult.
In Oracle of Seasons, there is only one large overworld map and second smaller "underworld" map. There are four seasons in the game, but unlike time periods in OoA, all of them share the same overworld map.
I like exploration like Link's Awakening (uncovering all squares on the map), but in this case, OoA is again worse - if this game is played first, one square on the Sea of Storms in the Present (surrounded by whirlpools on adjacent squares) cannot be reached at all. There is no problem with this if OoA is played second. OoS made this better - you can always explore all squares in both ways (played first or second, doesn't matter).