I'm currently a 4th year at Jefferson so I'll take a shot at your last question:
1. The people - The class is pretty big, but I have an amazing core of friends and have gotten to know my classmates pretty well. For the most part, everyone tries to help each other out and people are pretty laid back. Also, there are so many ways to get involved with different activities...there's around 100 clubs as well as intramural sports (I think there's something like 10 different lunchtime talks/activities going on this week), so it's pretty easy to find like-minded people.
2. Clinical training - I definitely felt that I got great clinical training, especially during 3rd year of medical school. The attendings and residents really tried to teach and give responsibility to 3rd year medical students, which doesn't always happen.
3. Location - Jefferson really is in the best part of Philadelphia...everything is walkable and you can really enjoy everything that Philadelphia has to offer
Hopefully that helps a bit. Overall, I definitely appreciated and enjoyed my experience at Jefferson and am really glad that I chose to come here.
Ultimately, it'll come down to whether you want to end up on the east coast (my class has 25 people who are from CA). If you're looking at places on the east coast, then Jefferson's definitely worth checking out. Good luck with med school interviews!