Ratings are based on a variety of features, including power, safety, and convenience. Power ratings describe how easy you can cut through thicker, tougher wood. Ratings show 10-inch blades should provide adequate power for most projects. Safety features are also important, including the ability to power off in an emergency, as well as the use of anti-kickback arms.
Consider the convenience features as well. A collapsible, low-weight table may be easy to transport, but it may not be as durable for large projects. A miter slot is an added removable feature that makes miter cuts easy, but can also make it possible to purchase add-on features down the road.
Ratings are also dependent upon a wide price range, as of 2010, from a few hundred dollars to a few thousand dollars. The most expensive are typically for contractors, whereas the lower priced ones are used for smaller jobs. Other affecting factors include stability and power, which will matter depending on the size of the job.