I think I do. I supported JC at the beginning of his time as leader, thinking he offered genuine change and appeared to be able to draw some support. His dealings with the PLP tarnished him for me, he seemed incapable of considering the bigger picture of voters who help you win government and support the party/policy vs voters who are part of the labour party membership and support him. I also think he isn't ruthless enough and never seems to properly capitalise on all the failings of the Torys over the last 2+ years.
That said, he represents the best option for a different government. The manifesto is great, and I genuinely wouldn't want any of the other candidates as PM. However, Labour would probably do better with the same policies and a different leader, IMO.