Considering the alteratives out there, I am thrilled by my Cami Secret.  I'm a 40D and my straps are not spaghetti-thin, but on my favorite Bali bra I attach the clips to the O rings that allow me to adjust my straps.  I don't have too much problem with bunching up (any product of this type is going to have to be smoothed ocassionally since it lays across one's breasts, which move)and none with twisting.

Having the option to wear all of my summer clothes without an additional layer is super exciting to me, since I always had to contend with an extra layer (not good when it is 100+ every day of summer) or cleavage (not good working at a middle school).  Several of the office ladies at my school swear by these and I ordered them in spite of the negative reviews here, since there were some good ones too.

Bottom line:  Yes, they could have better clips, but for what they are and what they accomplish, I'm happy to have them!