He did the tail end of SUPERBOY. Uninspiring, and failed to take real advantage of almost any of Kon's cool story-driving traits, but not necessarily bad.
On the other hand, I can't bring myself to give even a single percent of a damn about this incarnation of the team - it's an uninspiring cast, Alfred is a horrific fit for the part he's playing, Tomasi's done nothing to convince me otherwise, and he's used almost entirely bad cliches and weird unnatural story choices thus far, so I can't even care about the plot. So Didio's welcome to the book, he can't possibly make it less interesting.
Wish someone would poach Jeff elsewhere, though. He could be interesting at Checkmate, if Checkmate were relaunched with a competent writer.