I've been several times over the past few years and it's always an eye-opener and a bit of fun. I won't be there this year, though.
I was almost tempted, as I was having some difficulty finding a Chinon CE-3 body, but one came up yesterday on the Bay. It's just GAS, but I wanted to check out the last of the great M42 cameras that actually has aperture priority. The dimensions are about the size of a Pentax M body, and so the internal workings are probably similar - and as it happens I now have a range of pin-driven lenses, 28/2.8, 35/2.8, 55/1.7, and 100/2.8, as well as a 58/2 Biotar and a 500/8 preset - I don't know how I gathered all these as it wasn't really intentional ...
But Photographica is definitely a worthwhile mark on the calendar.