Is No Calorie Sweetner Bad for you?

My mother likes No Cal Sweetner because it doesnt raise her blood sugar up and I guess apparently she claims its sweeter then Sugar. Ive heard these sweetners are bad for you, People tell me Splendas ok for you and that Equal and Sweet N Low are horrible for you and full of chemicals. I was wondering if anybody knew what the good ones are and the bad ones are so I can buy her the ones that won't make her sick, Or are they all bad for you and should I be buying her something like Sugar in the Raw?