Not bad...I see that was shot at 200mm; is that a 100% crop? That's an awfully slow shutter speed for that aperture. Are you using spot metering mode? Did you have to back the exposure off at all in post?
Anyway, in my experience, it's hard to get a good moon shot with a 200mm lens, so well done. Yours is a little soft (I have the same problem, and only 6 MP to work with). To get it sharper, you could try bumping the ISO up a little and using a faster shutter speed.
Edit: Just took another look at exif data, and it looks like this was shot at 1/40s. That's a little more like it. Even so, try to get the shutter speed even faster, make sure you use sunny white balance, and don't be afraid to sharpen a little in post.