Both posters offered some good insight and to be perfectly honest whether transferring is a good idea or not is highly unique to each person's situation. If your career goals are to be a public defender in Wisconsin and your are currently attending law school at Marquette then stay there, rank in the top of your class, get scholarship money.
If your career goal is to work for Cravath then shoot for the T14, but even if you get into a T14 school it doesn't necessarily mean you will get into BigLaw, but you really will not have a shot otherwise.
Another factor to consider is your personality you know better than anyone else how well you can handle moving to a new location, meeting new people, etc. Some people thrive in this others struggle. If your a person who has worked all over the country, meet new people, blah blah then moving across country probably won't be a big deal. If on the other hand you have never left your hometown then moving across country to start as a 2L at a T14 school might be to much change.
Bottom line is don't simply transfer because U.S. News ranking says X school is #12. Once your out of the law school bubble the name of your school really won't mean that much unless your sole goal is to work in a big law firm. The people you meet, the location your residing in, your personal happiness, and what you want out of your legal career are all things that U.S. News cannot determine nor can any anonymous internet poster like yourself. I see a lot of people freak out about these rankings and make life altering decisions based on them alone and this is not a good idea. Remember it is a for-profit unregulated magazine nothing more and you should not make a life-altering decision based on it alone.
Hopefully some of that offers some insight or feel free to think I am full of s*** just remember anyone on this board or others is an anonymous internet poster that knows nothing about you, your situation, or what is best for you. The same can be about U.S. News they are a for-profit magazine and they cannot tell you what is best for your particular circumstance. In the meantime stay focused second semester and kick ass again.