I posted something similar a while back and it was closed, but I believe this post will be more suited for discussion.
I'm heading to Europe from the U.S. to complete my BS in physics. I intend on returning to the U.S. to complete a PhD (ie. no masters degree in-between). I'm aware that the European system has a three year BS program, as compared to the four years that are done in the U.S.
The central question is: Does having a three year BS affect admission into a competitive American graduate program?
From where I sit, I can't help but feel PhD programs will raise an eyebrow at applying with only two years of experience. All of the graduate application deadlines available online (Princeton, Cornell, Columbia) have a deadline of the 15th of December, which correlates to a little over two years of undergraduate education.
I've been lucky enough to have a huge head-start on the material (few formal credits, however), which means I could start research within my first year of study.