Here is a list of the 6000 iKnow vocab separated by WK level. It makes learning on iKnow much much easier: iKnow sorted by WK level
My mini-review: I think iKnow is a well-made, focused, distraction-free tool for learning vocab, that doesn’t require any work on your part to just do it. Recommend the mobile app for studying on your lunch breaks, before bed, on the toilet etc.