There are several ways to go when choosing a fly tying desk. For a very low price of around $300-$500 you can get a Taiwan particle board / MDF wonder that is sold by some glitzy web site from the city. It will come in a box and you can expect to spend a considerable amount of time assembling it. If you tie your flies in the basement or garage, don't care about looks and don't mind throwing it into the land fill in a few years this might be the way to go. The advantage is low price.
The next step up is a production, factory made desk. Some are OK some are junk. Some will have solid wood construction and others will use more particle board or MDF. Assembly requirements will vary with the design. Prices can range from $700 - $1800. The advantages are a moderately priced desk that will suit the broad range of fly tier's on a more limited budget. If you have measured expectations, can spend some time looking at construction details and features you can find a very acceptable desk in a lower grade hardwood that should function well. Also in this same price category you will find "some guy in a shed out in the foot hills" trying to compete. It's a hard road and most will be out of business unless they make a huge capital investment to become a production factory or take there design over seas.
The top category is a custom desk built by a master craftsman with high grade domestic or exotic hardwoods. This is were my business comes in. First and foremost I am a journeyman level furniture craftsman. I work out of a well appointed 2500 sq. ft. shop. Most of the time I work by myself but occasionally, when backed up, will have 1 or 2 helpers or apprentices. All my furniture is built one at a time with meticulous attention to detail and design. The advantages are top quality, choice of woods, custom features, matching custom side pieces, other furniture pieces, design consultation, direct contact with the builder and a piece of furniture that will last many lifetimes. No assembly required just uncrate. This type of desk will be a highlight of any well decorated room in the house. Prices from my shop and other legitimate custom builders can range from $2,000 - $10,000 (very artistic). These types of desks are not built for the masses.
The best advise is to select a desk to meet your needs and expectations but remember you do get what you pay for.