Gas-powered post drivers are great fence tools to have for driving in fence posts; but the type of gas post driver to use for fence post installation will depend on many factors.
For starters, the general homeowner using the tool for one time usage will not require a contractor-level post driver. Most of these post drivers that range in price from economical to medium-scale still contain small Honda engines. However, fence installers and contractors may want to upgrade to contract-level post drivers for heavier usage. These powerful post drivers will last longer.
Other factors will include budget and soil type - similar to ground stakes. Some post drivers will be better used for smooth soils while others may be better for harder surfaces.
When thinking about post drivers, consider multiple factors including how many projects will require the post driver; budget; and ground surfaces.