i do like her style, though it looks (like said) a little forced. i love how she rocks black, because it is my favourite colour.
but i don't think you can't compare rihanna to lady gaga. i am not saying that i like gaga's style (which i don't), but she has more authenticity to me. she was a dj and song writer, before being that big. she performed in underground clubs in new york. of course it is too much, but i do believe that it is her. she has more creativity. you can see that in every aspect.
rihanna was a beauty queen and we all know how she looked like when she started. i do know that people develop and change their style during time.
still, you can't compare them to me