But then there's the scary question: what if your stats don't measure up? In that case, many schools with programs like these just roll you over into the general applicant pool, same as early decision folks who don't get in on the first round. Your guaranteed spot is taken away, but you're still in the running. 

I do know 2 people who got in to a program like this. One realized after her sophomore year that science was not for her (as her science GPA was declining rapidly), and dropped the program in the same way that 90% of people who start out pre-med drop it. Nothing lost, nothing gained.

The other made it through and is now a first year med student. She would have gotten into medical school anyway, regardless of being in the program, because she was a top 2% type student. 

So where does that leave you if you're a student like I was, whose stats may not have been quite good enough for a program like that, but who still made it? It's worth a shot, but it may be less stressful to just gamble like everyone else does. 

As k-m-a-r-i-e pointed out, it kind of hinges on whether you want to go to the same school for 8 years or not. If you don't like the undergrad, I wouldn't waste 4 years there. You'd be better off at a school that you like that has a respectable science program, because you're more likely to do well if you enjoy the place you're in. And if you don't like the undergrad, you probably won't like the medical school either.

Also, you WILL change your mind at some point, even if you say you won't. I was determined to stay the course and not change anything, but I did. I started out undergrad saying there was no way I'd stay another 4 years and go to med school at my school. But I changed my mind (and my major), and I'm glad I did.