Not played Horizon yet (mine came today) but I've played 3 hours of Zelda on the Wii U so far and from the little I've seen of the game in my short time with it, the voice acting does the job but I've not seen a lot of it so far, this is not story heavy, at least at the start.
Gameplay is where Zelda really comes into it's own though, the world is one big sandbox and gives you a lot of freedom, kinda reminds me of MGS V, in just how fun the open world can be. The abilities you acquire are a lot of fun to use and can be openly used in the open world too, without going into too much detail.
Will have a better idea of how it compares to Horizon when I get home in a little while but from what I've seen, it looks a pretty different type of game to Horizon, with a big focus on survival and resource gathering.
Also the framerate is a little rough in places, on Wii U anyway but it never stopped me enjoying the game and it runs at 30fps, without dips in a lot of places too.