McClaren this season: P28 W6 (21.4%) D6 (21.4%) L16 (57.2%) GF28 (1pg) GA53 (1.89pg) -- 0.86 points per game
5 clean sheets in those 28 games, failed to score in 12
Benitez: P9 W2 (22.2%) D4 (44.4%) L3 (33.3%) GF11 (1.2pg) GA11 (1.2pg) -- 1.1 points per game
3 clean sheets in those 9 games, failed to score in just 2
He definitely improved them. Wasn't an ideal situation being appointed with the fixtures they had left, was always going to be tough playing Leicester City, Southampton, Manchester City, Liverpool and the other two teams in the relegation battle. If he had been appointed a few games earlier I think they could perhaps have stayed up. He stopped the rot in terms of conceding goals but they still struggled to score.
If he stays at Newcastle they could be better for it long term but I reckon they'll part ways and Newcastle will go for someone like Nigel Pearson.