Personally, I'm not a fan of either.
But I still agree Lady Gaga is a thousand times better than Justin Bieber.
Lady Gaga is just different, maybe not 100% original ( I find her to be a bit like Gwen Stefani, clothing style-wise )
Whereas Justin Bieber is really just another pop-singing kid. That type of stuff tends to get old.
I applaud the guy for following his dreams, just please be a bit original.