'N Sync - It looks impressive ('Cause it's fast) but really it's not that difficult. It's almost impressive, so even if it was hard it wouldn't take them that long to learn ANY ROUTINE THEY HAVE DONE.Backstreet Boys - Depends. Pretty medium (better than 'N Sync).
Britney Spears - Yes, she is relatively good. But not as good as
Christina Aguilera - Not only can she do steps, but she has great stage presence and can count music VERY well. You go Christina!
Pink & Sisqo - In Thong Song and Most Girls they don't do much dancing, mostly acrobatics. However the acro elements are really good.
Destiny's Child - Sorry girls, but you have to learn something more than jumping up in the air and swinging your hand like a lasso.
2Gether - So horrible it's funny (I think the sucky dancing is supposed to be intentional).
Janet Jackson - Still awesome after all these years. The tilting dance floor scene (as the floor actually did tilt) is very impressive.
Jennifer Lopez - In If You Had My Love and Feelin' So Good she looked very good. The steps aren't that hard, but the way she can do them (as in presence, etc.) are awesome.
Well, that's about that. I just wanted to clarify (especially since if I hear somebody say "The dancing in Bye Bye Bye was tight," again I will scream very loud).