Very simple, it's just two lengths of square tubing, a platform for the miter box, a couple of plywood boxes and some t track. I really like t track, because it's a convenient way to use stops for precise repeatability and for hold downs. I used this work station a lot with my chopsaw when I did carpentry work on my ranch. I could carry it to where I was working and set it up on sawhorses. In part, my miter box station is this way because that's what I had on hand, and, in part because, being portable, it is compatible with a small shop. It could be stored on a shelf and put on the workbench for use.
This miter box is a Millers Falls Langdon Acme that I purchased (with no saw) at a garage sale for $4. Many believe it is one of the best ever made. They are amazing tools, extremely capable and very accurate. You sometimes read that miter boxes aren't accurate, that they are off a degree or two. Possibly, but I think that view may sometimes stem from not realizing that they can be adjusted, something I learned when I disassembled mine for derusting and cleaning. There is a threaded brass bushing with an off-center hole in it that is used to micro-adjust the angle of the saw. I fussed with mine until I got it dead on. I suppose there is some slight play in the guides but it's very small. Something else you may not be aware of is that the miter box can be adjusted to cut a board as wide as 10 1/2" at 90 degrees. There are brackets on either end of the base for cutting crown molding or other compound angles which I'd like to try. There are depth stops on the guides and I think it would be interesting to try defining dados with them. I suppose you could also cut tenon shoulders with them.
If you are interested in more information about this miter box, the original instruction manual can be downloaded here. I know there are other good ones as well, but I don't have any experience with them. To the best of my knowledge, there are no good miter boxes currently in production. Intriguingly, though, Lie Nielsen states on its website that "[w]e are not yet making a miter box but we do have plans..."