To be honest, the only thing I really didn't like about all this was the horse-ness. I don't think the year of the horse is enough of a connection for them to excuse having random horse sounds in the song, a song that sounds great up until the weirdness of horse sounds. The last horse part kinda made sense because it was set up by the whole country western theme going on during the ending, but just random instance in the song really bothered me, especially since the song comes out as really serious (at least to me it does...).
The horse dance break too was ehh. All the workout/punch moves were ok, I can live with those, it shows that they "worked hard" and "maintained stamina" to be idols for 10 years, and they didn't do it TOO much that it got past acceptable weirdness.
The girls looked good, the set was nice, the dance was ok, the song is great, just no more random animal sounds in the future, please

On that note, I really hope they tricked out the PV for Ai wa Itsumo.