Large wheelchair manufacturers like Invacare, Everest & Jennings, Quickie, and Permobil have the money and resources to produce excellent chairs. Who is selling you their chair though, they’re the distributors? The retail dealers actually sell you the chairs.
A smaller manufacturer doesn’t have as much money or resources to get your attention. In most situations they are more willing to go the extra mile to make sure you are happy with their products, because they are both the manufacturer and retailer. The one drawback to the smaller wheelchair manufacturer is that they may not have all the bells and whistles that may come with the R&D that the big companies have access to.