I finished undergrad in 3 years with no AP class credit or anything from high school while double majoring in biology and chemistry. I did take class year round meaning I had to sacrifice my summer for school.............But, It does mean I get to earn a living 1 year earlier than my initial cohort.
DO NOT let graduating early sacrifice your grades! I had to take 18+ Credits every semester and ~12-16 each summer. For many people, that is just too much! Or if you are just some kind of F-ed up, like me, and enjoy taking Advanced Organic Chemistry and Advanced Inorganic Chemistry as your senior 'electives' than go for it.
I'm not the smartest cookie in the jar, but I do have a good work ethic and great time management - which allowed me to keep an above average GPA (graduated Magna Cum Laude).
When it came around to interviews, I had 2 schools tell me they dont interview the 3 year non degree students. . . After I explained to them I actually had my degree in 3 years, they were impressed and I got an interview. At IU, all three of my interviewers were very impressed that I was able to graduate early, keep a high GPA, and maintain strong leadership roles in various campus clubs and honor societies.
Basically, what I am trying to say is that it is difficult but as long as you keep your GPA high and maintain a good time management system it will greatly benefit you.
Hope I could help you with my previous experience!