Of course his renders weren't as good as some of those artists you mention, though I can say his latest work was much better quality than the earlier ones. But I liked his art because (1) the severity of the torture, (2) including rape, but not dwelling on it, (3) continuous stories, unfinished or not, and little or no breaks in the victims ordeals, (4) He was very prolific, and to me, that made up for the difference in the imagery compared to others.
His style of renders and characters may not appeal to everyone, but he was a great creator in his own right no doubt.