For what it's worth, I've been to a few recruiter places lately and they all mentioned to show my folio on an iPad. One even mention they hadn't seen a folio like my for a while (over sized A3). I have...
I love the use of letters and numbers as building blocks for a bigger picture, however, this design doesn't quite work for me as it is. I'm not sure of the type of design work you do but this logos makes me think of kids and clowns.
Also, I wonder if somebody looking at it would think "oh how clever, the name of the business is Steve Scott Design and he used 2 S's and a D in his logo!" or will it be one of those things you're always trying to explain?
It might work if the whole vibe of the business went with the whimsy of the logo though. If the styling of your website (assuming you'll have one) and invoices/letterhead/ect. has this same playfulness, done in a very professional way, it just might all come together.
Have you played with the idea of using some sort of element to act as the "head?" Maybe a splat of paint or something would make it look more specific to a design business.
"Since we cannot know all that there is to be known about anything, we ought to know a little about everything." -Blaise Pascal
personally i would stay away from using initials in your logo. I have seen a few people try it now and post them here. it would be better to use your whole name and find a typeface that can become your logo. or design a symbol. but goofy things with initials is not the answer.