The reason they are more covered up is because the Grammy's released a set of rules stating that outfits had to be respectful and performances had to be too, as after all it is an upmarket awards show. I can see how this links to Gaga's craziness though xD
I think they both look great but I don't like the dress code thing. These are artists that are attending, let them do what they want. To me it feels like they are saying that the female form is a terrible thing and should never be seen. It's just a body, no big deal.