For me, it often depends on the machine and how quickly I need to move it. If it's newer, in high demand, and I'm not in a rush, I'll lean towards selling directly. You can usually squeeze out a better price that way.
However, if it's older, has higher hours, or I need to free up space or cash quickly, dealing with a reputable dealer can be the easier route, even if I take a bit of a haircut on the price. The convenience can be worth it.
My biggest piece of advice - know your equipment's value. Do your research to understand what your machine is worth on the open market and what dealers are typically offering. And remember just because something is listed at a price, doesn't mean it's selling at that price.