I enjoyed it. Nathan Fillion was great! Nolan North also did a wonderful job with the new material.
I specifically enjoyed the dialog in the Last Rites mission. Fillion's line about the Hive being in the middle of some kind of funeral made me chuckle. I also felt a sense of urgency when you're exposed and Ghost yells "everything is corrupted."
Cutscenes were great. Quests were great too. I'd like to see more of everything TTK has going for it in future installments.