I'm planning on doing it at some point after my rigid test (you have to take them in order now... )
I'm not intending on doing it for a living, but it is another string to my bow, and a mate of mine who I sometimes help out, now runs 18 tonners (since I got pulled for overloading one of his 7.5 tonners) so I will still be able to drive for him occasionally.
I had a go in an artic today at work. Great fun, but I got grease all over my trousers connecting the air lines!