I have been using Zenni for over 10 years and have always been happy. I wear progressives and haven't had any trouble although my prescription isn't complex. As far as fit goes, you upload a picture of yourself so you can try on the frames and the pupil distance numbers make sure the lenses are centered correctly. It lets you sort out the frames that don't accommodate bifocals or progressives. The only trouble I ever had, which was my mistake, was to order the plastic frames that don't have adjustable nose pieces. I had forgotten how those things slide. If the frames are wonky on my face when I get them, I take them to my eye doctor's and have them adjusted at no charge. They make me sign a waiver that they are not responsible if they break them. That did happen once and I went home and contacted Zenni. They sent me a new frame immediately with instructions on how to switch the lenses. No problem. I love Zenni because of the progressives, I couldn't get a pair at the local eye doctor for less than $500. I spend about $150 at Zenni.