I'd like to like the Knipex, because of the lower cost. But, they haven't held up for me. I cut a lot of piano wire, and it needs to be cut sharply and precisely. SO 87AC's are the only cutters (except an old used pair of SO vac-u-grip) that have held up. Knipex and Klein (who I also really like) don't last more than a few days.
I asked my driver what he had that would work, showing him the Kleins, Channellock, and Knipex that hadn't held up. He told me that the 87's would work fine, and he'd refund the purchase if they didn't, and replace them if they work out after working satisfactorily.
I've been using the SO 87's for over 4 years, and they are as sharp as the day he sold them to me. The knipex round nose pliers that I bought at the same time have worn out in that time. I'd buy a pair of SO in that style, but they don't have them.