Just about everything! Most furniture stores sell pieces that are mass-produced overseas (China) in the cheapest way possible. Nonskilled workers use machines to mill out inferior wood to size and then assemble it (or send it to the store to be assembled). Wood is not selected based upon its grain, strength, or appearance-but rather by its cost. The stain is applied in layers on top of the wood to blend non-matching wood (which blocks the grain and results in a bland finish). Traditional/long-lasting joinery is not used. Custom sizes are not available. You get exactly what they have–nothing more. These pieces are designed to last for a couple of years and then be thrown away.
Custom furniture, however, is custom designed for YOU! It builds the exact size to your specifications and uses the very best wood possible. Carpenter sort for grain match, color, and strength, and inspect every board fully to ensure it meets the stringent eye. He uses time-tested joinery and custom fit each joint to ensure optimum strength. Custom furniture is designed to last for generations with proper care, and will be passed down proudly! Carpenters often use no stain (selecting the proper wood for the color you desire). If stain is desired, then it hands rub high-quality stains/dyes into the wood to accent the grain rather than hide it. And then hand apply multiple coats of a quality topcoat to protect the wood. Make no mistake, the custom manufacturer cannot compete with China’s pricing, but they cannot compete with quality, customer service, and uniqueness of the product. The latter is of true value.