All of the admissions committee members I've interacted with are super friendly people. The idea of being interviewed by three people at once is daunting, but everyone I've talked to about it says they settled in pretty quickly once the conversation started going. An important note to remember is that they'll ask questions pertaining to the AAMC's Core Competencies, so it is very unlikely that you get a question designed to throw you off. I went on multiple MD interviews and OU was one of the more laid back ones.
The closest family I have lives two hours away. I went to OU mainly because of the opportunities OU Medical Center and the clinics under its umbrella offers. OUMC is the biggest hospital in the state and gets all the big cases in a pretty large radius, which means there's tons of opportunities to see cool/rare cases as well as opportunities to explore tons of different specialties and sub-specialties. Also, as the only MD program in the state, you have access to endless alumni connections and resources meant to help you succeed. Furthermore, you'll come to find out that OUHSC gives out a lot of scholarships and financial aid in comparison to other similarly ranked schools, that's a big reason why lots of people who get into multiple schools end up coming here.
Pre-clinical grades (M1 and M2) are true pass/fail, they were on a honors pass/pass/fail system until this year but now it's strictly pass/fail. Clinical grades (M3 and M4) are either pass/fail or a traditional letter grade system, depending on the individual rotation. That's the case because most residency programs still want to see how you did in comparison to others in that specialty's rotation.
In terms of competitiveness, we have a pretty collaborative environment here. The module system does a lot to build friendships and mod mates will always share Anki decks, study guides, or any information they find out from upperclassmen about a particular class or exam we have coming up. There's also a Google Drive that's passed on from the class above which contains all sorts of study guides, practice questions, etc.