Direct drive (aka gear-driven or forced rotation) polishers use a toothed gear mechanism. It has both movements found on a normal DA Polisher but rather than the backing plate “free spinning” it has a geared backing plate. Think of it like the childhood favourite Spiraliser, the same periodic movement over and over to give you consistency.
Although a little heavier than the others polishers, Direct Drive Gear Driven Machine Polishers give you the best of both worlds; all the cutting power of a Rotary, but with all the safety of a Dual Action. More cut, fewer holograms; a real goldilocks story. Rotary's can skip if not level, DA's can vibrate a lot if unbalanced; you won't get any of this with a Direct Driver Geared Machine Polisher. These machines are one of the smoothest power tools you would ever use and are very quiet.
When you start detailing your car, many enthusiast, and professionals choose a Rotary or a DA, with options to suit all budgets and flavours. As their talent improves. They may look to upgrade their machine. This comes about the same time that their older polisher is giving up the ghost. As many do not know about Direct Drive Polishers, they are simply overlooked. The other reason is mainly of the cost and weight due to having all the extra mechanical parts. However, if you look at the difference between a top end DA and Direct Drive prices and how much time can be saved with the additional power; for a professional this would be made up in time spent on a job quite quickly. That said, if you are a beginner with a healthy budget, it presents a great solution for a starter machine; you will never need to “upgrade”.