I been there. I once ended up there on a Saturday night and it was a night club with people dressed up straight out of the roaring 20's. Apparently it turns into a club at night. If you get the change it is worth checking out. If you are in the area walk over the "The Last Bookstore", also worth a look.
Nope, there is 100% still a cafeteria. They renovated a few years ago, restored the exhibits, and it’s now pretty nice again. The food’s good (like, throwback cafeteria food good, not “good” good. Get the meatloaf.) There’s also a tiki bar on the top floor. Unfortunately in an annoying LA trend the door to the tiki bar is hidden behind a mirror.
I ate at Cliftons some years ago, before the remodeling. It was pretty cool but also pretty worn out. Standard cafeteria fare, nothing really exciting. Mostly it was about the ambience. Some of the interior decoration (i.e. the fake animals and natural settings) looked like it had inspired Disneyland's designers.
We moved from SF to DTLA 2.5 years ago. I never been before, but even within the last 2.5 years it improved significantly. A lot of new apartment buildings were built and a lot more are under construction, pushing rents down significantly. We went down by 50% on our rent between SF/LA and now we went down by additional 35% within last year and it doesn't seem to be stopping. A lot of the building are still quite empty and doing everything to attract tenants.
The inflow of new people is also bringing new restaurants and other places. DTLA is quite enjoyable these days.