We did our Ark. tour a few weeks ago, with similar results - it's now my senior's top choice. He also toured UT, Tech, UNT and TCU. He felt UT was too big and, as a parent, the tour was pretty lackluster compared to the other schools (they don't have to do too much because of demand, I guess). He really liked TCU, but I just can't stomach the cost even with merit-based aid.
Arkansas was gorgeous, really rolled out the red carpet for prospective students, and is a bargain given the aid he's eligible for (32 ACT and 4.0 GPA). He wants to do poli sci, which worried me given the state's overall politics, but the school seems well-regarded and pretty even-keeled in terms of overall nonpartisanship. I really hope he sticks with it as his top choice - I'd really love to make the trip up there for games and general visits every so often. One of his closest friends is leaning towards Ark. for the architecture program, which may also influence his decision to go up there already having a potential roommate.