You can buy unfinished furniture in a variety of styles and constructed from several different types of wood. In addition, when you are shopping for unfinished furniture you will likely find pieces that can fit just about anyone's personality and budget.
Where as when you purchase unfinished furniture and finish it the way you want it, you have high quality furniture with a touch of your own personality; when you buy furniture that is factory finished, it is a replica of thousands of other pieces of furniture that looks exactly the same, and it won't be near as high quality as unfinished furniture.

When you purchase factory finished furniture as apposed to unfinished furniture, not only is it much more difficult to determine if there are any defects, but it will not be very high quality, regardless. Factory finished furniture is often constructed of a combination of wood and particleboard, making for some very low quality pieces that will not last too long.
On the other hand, when you choose to purchase unfinished furniture you will be getting real wood furniture that you can easily examine to ensure that the wood is in good condition, and the craftsmanship is up to standards. In addition to this, you will likely spend a lot less money on unfinished furniture than you will pieces that have already been finished in the factory.

Aside from the quality issue, when you purchase unfinished furniture you can easily add your own creativity to each piece when you finish it yourself. Creating the room that is a reflection of you, is much easier done if you can finish the furniture the way that you want, instead of simply compromising with furniture that is close to what you want.
Unfinished furniture also makes it a lot easier to match your room's color coordination, and the other furniture that is in the room. Nothing can be more frustrating that finding the perfect piece of furniture to add to your room, but the wood is light colored and the rest of the furniture in the room are constructed from dark wood. With unfinished furniture this need never be a problem, because you can make any piece of furniture match what you would like it to match.
When you buy unfinished furniture it's easy to create the home furnishings that you want. All it takes is some stain, top coat finishing, and you have a beautiful piece of furniture, that you not only created yourself, but at a greatly reduce price off those finished furniture pieces.

Don't compromise on the furniture for your home, save yourself some money and buy unfinished furniture that you can be creative with and display a masterpiece, instead of a factory mass produced piece.