Who for?? If your son then going frameless at this stage is probably a 'bridge too far'. Unlike you and me, he is getting stronger as he gets older and won't feel the weight penalty so much - advice from my daughter who thinks I fuss too much about weight. It dosen't bother her much at 17yrs.
Not found mine fragile in the slightest. Its been the only pack ive used in the hills for over a year now and it still looks new. Carries really well but obviously thats a personal thing.
I also have the blaze ac60 and thats going strong after 3 years. Tends to be my extended trip pack so gets some proper miles.