Duffy vs Amy Winehouse

I almost hear these two songs played at any gym club: Rehab and Mercy. I thought both songs were sung by same singer, which is Amy Winehouse, because of the low, yet strong voice. Well, it turns out Mercy is sung by Duffy, which I even never heard the name before. Amy Winehouse is now so popular because of drug problem. But, after listening both songs at youtube, I realize their voices are quite different. Do I get confused because of "yeah yeah yeah" vs "no no no"?


After doing step for 1+ months, I grow to get addicted with the class. Everytime I go to gym, I will try to suit with the step schedule. Last night, I try to go to Daniel's class at Raffles although it's quite early, and I need to rush from office early, with the "you-are-not-busy" look from colleagues. There're a lot of regulars, that can modify the movement until unrecognizable movement. As beginner to level 2 class, I get a bit confused of this expert's variation and some memory issue, but I enjoy :).