Justin Holl has repeatedly been underrated by fans due to his style of game. While he is not the perfect player, he is quite strong defensively aside from the glaring errors he would make every couple of games.
Holl has played 285 career games, all with the Maple Leafs, and has established himself as a valuable NHLer. While he is valuable, many do not see him as more than an okay 2nd pairing defenseman.