I do think that people who are good looking get promoted faster and above others. I also do think that they do tend to slack off as they are always loved by everbody so get carried.

Hope I haven't offended anyone just things I have noticed over the years.
As an exceptionally good looking person I take offence to that!

Seriously though, I once read a study that said people like people who are like themselves, and if they see a good looking or charming person (because charm makes you attractive) then they see themselves in that person and hence why they are more likely to see their good points and promote them. I think a very good looking person who is bad at their job will still struggle. However if two people are both adequate at their job and one is physically attractive to their boss and the other is not, then the attractive one will be more likely to get the promotion.