Hewitt definitely has the edge. Probably one of the top volleyers of tour out of players that predominately play singles. He didn't rely on them that much because he never had enough power in his groundstrokes/serve to get to the net consistently.
Hewitt's a beast at net. Pity he's only 150cm tall, and like you say, doesn't often get into net.
THAT being said. Hewitt's serve is also underrated IMO.