I'm wouldn't recommend it. Advantages/disadvantages aside, you're likely to become burned out.
I entered college at 16 with no plans to rush through anything. Somehow it ended up that way. It's only been three years, but by the end of this year, i'll have completed two bachelor's degrees (basically two BSc in three years). I utilized every summer.
The thing is, i'm exhausted. Beyond exhausted. At a certain point, after months without any sort of break, I lost interest in what i'm learning. While the material is interesting, I have lost the motivation to do as well as I have done in the past two years.
Now, I don't want to graduate because i'm only be 19 and there's no use in applying to med school. I have no idea why I rushed through things and what i'm going to do now. I can either take the year off and find something constructive to do (catch up on sleep?) or lower my courseload next semester and take my last few remaining classes next year, extending my stay by a year. In retrospect, I really haven't enjoyed these past few years. I've sacrificed other things i'm passionate about for the sake of taking on this huge task of completing two degrees in three years for a purpose i'm not yet sure of.
From my understanding, (and I haven't read all of the responses, forgive me) there really isn't an advantage to graduating early. If you really want to speed things up, get the majority of your coursework done in the first three years, and spend the last year with a lighter courseload or classes that interest you and do research, volunteer, etc.