That machine comes relatively complete, but a lot of optional goodies are available to suit nearly any application. Consider what features would best fill your needs, and buy accordingly.
For example, if you intend to join a LOT of frames, then the gluing system is for you. I simply don't need it for my level of production.
And no matter what your usage requires, I recommend buying the lubricator/filter. It is an excellent value. By assuring proper lubrication, that option means you might retire before any pneumatic parts wear out.
With my Fletcher 5700, I ordered side-wing supports, all sizes of v-nails & spacer-bars, the floor stand with utility box, and the filter/lubricator.
But before my 5700 arrived, I changed my moulding room layout and ended up canceling the side-wing supports. Instead, I placed the machine in a corner and built 16" wide shelves off both sides of the machine, which support the rails nicely.
Promise you won't laugh? I have my miter sander, v-nailer, and compressor in a 5'x8' former bathroom. The way it's set up, I can v-nail a 48" square frame easily.