I just wrapped up our Age of Worms campaign myself last week. Five players and we were running it in 4E. The campaign itself was excellent and we all had an awesome time, except for my monsters.
But 4E will never see the light of day at my game table again. The fight with Kyuss took over 4 hours to complete and there was only a single PC death during Kings of the Rift. I had Kyuss, a 30th level solo of my own design up against the party of 24th level PC's, and he couldn't kill a single one of them. Every time I thought a PC was dead, they had some silly power that let him come back to life again, or another PC had some item or power that would put them back into the fight on their next turn. It was pretty ridiculous, and fairly anticlimactic for me as a DM.