Neil Gaiman's previous episode, The Doctor's Wife, was one of the best episodes the show has ever produced. Unfortunately, while his return episode was entertaining it was also very flawed and featured as many moments of idiocy as it did genius.
Firstly the positives. The new look Cybermen were fantastic - a brilliant melding of the new series Cybus Cybermen and the original series Mondasian Cybermen. Gaiman was also pretty successful in his attempt to make the Cybermen scary again - the moment where one moved at super-speed was a fantastic reinvention of an enemy that usually gives you days' worth of warning as they slowly clank towards you.