I'm a graduating 4th year med student at Penn. I personally LOVE it here, and have no regrets about my experience. Anka is right on... we're very supported in the preclinical curriculum, and for residency apps.
As for moving up the time to clinics by 6 months- I think it's the best thing that's ever happened to the curriculum. Once you do a few months in the clinics, you'll see that learning minor details in pharm and micro really is not that important. On the other hand, you get 6 months extra of electives and research time to get yourself ready for residency and residency apps, and to make certain that you are making the correct career choice in picking your specialty.
I disagree with Anka that Penn is hands off in the clinics. I think it's very person dependent (as are all medical schools). I always showed initiative, and was able to do many procedures (many blood draws, arterial blood gasses, lumbar punctures, thoracentesis, paracentesis, intubations, laceration repairs, etc.). I think Penn does a great job of making the students feel like they are directly responsible for patient care, and this goes a long way.
A great thing that Penn does is that students take over for an intern on their sub-I rotation. Most schools have two students take the place of an intern, but Penn has you sub directly for an intern for a month. After doing this, I know that I can handle internship, and was able to learn a ton.
Good luck with your decision. I love it here, but make sure you pick a place that fits your personality.
Q