I personally like the Inverse Battle house. It stresses additional thinking about the type matchups, which if you know rather well can form a fun twist/challenge. Unfortunately, since there's only one house (on Route 18) and it's a daily event, it kind of disappoints me that this wasn't further implemented (i.e. more trainers willing to inverse battle, like the sky battles, or as mentioned earlier, made a Wi-Fi/Link Battle clause)