I have played with Win 8 Metro only a bit, so I can't speak for it's practical usage, but I own a WinPhone8 (Lumia 920) and the UI i think is not at all overdone, and other than tiles having their non-standard images sometimes, it's all very consistent (except for the few apps that are e.g. ports from Android or iOS, which use non-standard UI, but that's the developers' faults, not Metro's).