My personal opinion on the reason the deliberations took so long is there were one or more jurors holding out on the guilty verdicts. Those jurors know there will be a penalty phase, and, possibly in about 100 years, he may get the death penalty.
Yeah...that's the only thing. All the death penalty is going to mean for this guy is that he will be kept isolated and protected from the general prison population. Death penalty for murderers of adults is probably as severe as punishment gets. But, from what I hear, being in the general prison population (especially certain cell blocks and the guards usually know which ones) for ANY child murderer/molester would be MORE severe than the death penalty for this guy.