I am a part of many sites on the SE network, but the two I am referring to are Anime & Manga and Arqade. In A&M, I unlocked the ability to access review queues at 350 rep, while this privilege is not attainable in Arqade until 500 rep.
I've read some other questions, such as Why do certain sites require more reputation for privileges? that also address this, but they state that reputation levels differ when sites are still in beta. However, neither Arqade nor A&M is in beta (public or private) to the extent of my knowledge, so why do the reputation levels vary for the same privilege?