So apparently pic related has had a firmware update which improves the manual focus and auto focus.
https://www.youtube.com/watch?v=jfvO-0ZVQf4I've been put off buying this lens due to all the complaints about the manual focus being pretty bad and the auto focus struggles in low light.
Does anyone have before and after experience with the new firmware? I will buy this lens today if the update has fixed, or near enough fixed the issues.