Yes I use it, but not because I have poor performance and need something to cure it. I spend most of the winter months in the north and use Howes Lubricator which claims to clean injectors. I use it for the cold weather fuel treatment for much of the winter and by default I'm also getting an injector cleaner (or so it says in their product info).
In the summer, I use Power Service Diesel Kleen occasionally, but I honestly don't know if it's doing any good. With the crazy high injection pressures (35,000 psi or so in newer engines), I don't mind spending the money to try keeping everything in optimal condition.