I think my favorite songs from GACKT include Last Song, ANOTHER WORLD, Jesus, GHOST, Vanilla, Mizerable, FARAWAY and Papa lapped a pap lopped, in no particular order... I can never get tired of those
I don't think any of his releases are "bad", but I do think he does get rather repetitive sometimes. Some of his newer songs sounded like "more of the same" to me, like Arrow... it's classic GACKT sound, but imo it didn't stood out because it sounded like many other songs from him.