I have, and originally I was going to go that route but when we bought the house it needed a new pool liner and the company that did it (and was going to do our saltwater upgrade) pissed me off big time and I canceled the saltwater part of it.
I am happy with how things are now and not sure I'd consider saltwater. A big part of my decision was the fact the salt cell doesn't last but a few years and is expensive to replace, costing almost as much as the chlorine used in that time frame.
I guess no matter what you do it's a hole in the ground you throw money into.