When DC Comics announced that Jim Lee would pencil the Batman: Hush arc, I remember taking bets with my friends for how long into the run Lee would get before he quit. At the time, like most of the original Image creators, Lee was known for missing deadlines and extended hiatuses. We never questioned the quality of Lee's work. It was his ability to turn pages around on a reasonable schedule that made me dubious about his Batman run. To my surprise, Lee held up his end with nary a delay.
Jim Lee's tenure at DC marked a sea change in his career as an artist. His work was always good, but Lee became a great artist and phenomenal visual storyteller under DC's banner. While his Marvel and Image work isn't without merit, most of the iconic drawings from Lee's career stem from his time at DC. I don't believe that to be a coincidence. In the video linked above, Lee sketches Batman, the very character that became synonymous with his artistic evolution.