Our rescue has a very strict "do not declaw" policy. Why? For several reasons. Firstly, it takes away the cat's natural defenses and ability to climb. If the cat should escape from the safety of a home, it is left defenseless. Additionally, the procedure itself is quite cruel. Many have the impression that declawing is comparable to trimming finger nails, but to the contrary, it is comparable to having a finger amputated at the first joint. This can have severe and permanent physical and psychological effects on a cat.
So how can cats and furniture peacefully co-exist? One thing is to provide the cat with plenty of scratching posts. They don't have to be a lot of money - the corrogated cardboard products available at local pet stores seems to be very popular with many cats. Additionally some wood, carpet scraps and a couple of nails make a great scratching post! Keeping the cats claws trimmed can be very helpful. And placing double sided tape on furniture that seems to be especially interesting to cats can be a major deterrant, as is a well-timed squirt with a water gun.
There are many effective alternatives to declawing. And leaving your cat with claws will keep your kitty happy and safe for years to come.