Murray and Djoko are both adequate at net. Neither is real good. Both would be better players if they attacked more. Watch the 4th set tie-breaker in AusOpen 2012 final against Nada. Leading 5-3, Djoko had 2 points where he was inside the baseline, nailed a drive deep into the corner, had Nadal scampering 10+feet behind the baseline and Djoko retreated both times. Nadal hit weak floaters to reset the point and Nadal went on to win both points and the 4th set. If Djoko had come in on both of those points, 99% probability that he wins the 4th set and Djoko would have never had to play the 5th set. Same thing in Djoko victory at Wimby - he let Nadal get away with the 3rd as Nadal played 10 feet behind the baseline and looped the ball.
Djoko won both of those matches in spite of his unwillingness to attack.