Ite, so I am a Chofetz Chaim Senior. I have the same issue. I’m looking into Vancouver, WITS, and Miami.
From what I researched: Miami and WITS are the more intense learning Chofetz Chaims. WITS has a gorgeous campus. Miami is in Miami ;).
Dallas, and Vancouver, are both gr8 places too. My Cousin is in Dallas, from what it seems he loves it. Vancouver; I have a couple of friends that go there, and they seem to be as Happy as can be there. I met one of the Rabbis in Vancouver he seems to be really nice.
City wise, Vancouver beats Dallas (Hands down).
But you shouldn’t go to a school just 4 the location.
Hatzlacha!!