NZXT C650w vs Superflower Leadex ii 650w vs Seasonic Focus Gold 650w
NZXT C and Seasonic Focus Gold are essentially the same. Super Flower Leadex II is very close to EVGA G2 which is very good too. So yeah, they're pretty much all good, although i reckon that Seasonic should have better consumer support. Keep in mind tho that if you plan to ever use AMD Vega GPUs (or similiarly power hungry GPUs like older AMD R9 280-290 or perhaps smth in the future) then you better off with NZXT or Super Flower because if Seasonic Focus Gold (it's older model which has been replaced by Focus GM/GX which NZXT C is based on) has compatibility issues with those GPUs.