though in reality, today the difference is almost academic. One Wilshire is known as _the_ carrier hotel in Los Angeles, if not all of the US. The 4th floor meet-me room was widely known as the most expensive real estate on the west coast, at one time.

While many large, international networks still setup inside One Wilshire at a premium, if I just need cross connects, I can get them for exactly the same price inside Wilshire Annex -- a more "colocation for server farms" oriented building that is slightly cheaper and much larger (for individual spaces, not in total conditioned square footage, iirc).

Why do large international carriers pay the premium for being in the "carrier hotel" One Wilshire? Because they don't want to rely on CoreSite (the buildings and associated interconnection infrastructure management company) infrastructure. They want "home runs" to the other large international carriers they interconnect with and sell to.

If you aren't ATT or AWS, there is little need to be inside One Wilshire -- except perhaps for the "prestige" factor.