Xroc's description is much more eloquent than mine will be. Also his is mostly positives about the day...for balance and clarity, i'll brain dump what i found to be the negatives -- some might be nitpicking (which i feel will help eliminate any unwelcome surprises and improve your experience as future interviewees):
Day starts very early (i.e. told to be there by 7:45...which means most were there around 7:30. Yuck!)
A lot of day is spent in a study room in the library, doing introductions, listening and TBL'ing... the library isn't bad. But i wish the SOM had a freestanding and independent building just for them. Sharing library and space with undergrads is kind of a downer.
The interview group was the largest i have seen... 20+ peeps. You will be required to stand up and briefly talk about yourself, while feigning interest about the 18th hard science major in a row (yuck again).
The tour is a good bit of walking outdoors...this is rough in a full suit in the hot sun.
TBL has several steps and takes about 45 minutes. Personally, i was not a fan. It is well-developed and i can see the value they try to attribute to it. But it really sounds inefficient and like a time sink. That said, most schools now have PBL/group work implemented, so what can you do?
Lecture attendance is mandatory [in a sense]... if you drop below ~70% attendance it will hurt your grade, iirc. HUGE downside in my book.
The shuttle to the hospital for us was about 40 minutes. This can be a bit hot if ur sitting in a full suit, in a window seat in the sun, surrounded by 20+ people. Also this lends itself to a lot of small talk that you may/may not want.
The interviews from my own experience and others i talked to seem to be a mixed bag. One of mine was with a very cheerful doc that was praising everything about me, the other was with a much more serious doc that grilled me on my research and EC's.
Lastly, as a small school, there isnt much of a collegiate sports scene worth cheering for...if you're into that kind of thing. And the Lions? Sigh.
All those negatives said, I enjoyed the overall experience and feel that OUWB will be a nice school to attend. The staff/faculty were very kind, beaumont has great opportunities and i loved the areas of auburn hills/royal oak.
I could see myself here if the $$$ is right.
I love OU! 
