Looking at both spinner’s spun articles, they both seem to generate spun content that looks pretty good. Both have some grammar issues I would correct if I was posting it on a high tier 1 site, but overall SpinnerChief produced better content. Not sure if WordAi is being overly aggressive on the spins at the cost of quality. This test is very hard to call. If you go by raw numbers, SpinnerChief won. I want to leave this up to you to decide which one won. Winner none – draw!
I've ranked websites in the past with spun content, and now they are still on #1 position of google. First year (2014) google found me because my spun was really bad, many paragraphs were just copied and my position drop from #2 to around #20 after a panda update. Later I cleaned all my text with better spun (I didn't buy any article!), my ranking went up again, and with more backlinks I reached #1 and it is still there