And, by the way, the large majority of networking appliances (routers, switches, ATAs, etc.) all have the same fixed username of "admin", and only some vendors allow it to be changed. It makes management of multiple such devices a bit easier for, well... the admins.
From a strictly pedantic perspective, a different username might make things more secure, but in the real world, like Geoff pointed out, a strong password is reasonably effective.