Iron??
There may be a reason ferrous sulfate is best for someone, although I can't think of what that would be. Do you know why your doc recommended ferrous sulfate for you over carbonyl? Some docs have said they recommend ferrous sulfate because they don't know the difference between different types of iron and that's just the one they are most familiar with.
Please note: I AM NOT A DOCTOR. If you want medical advice, talk to your doctor. Whatever I post, there is probably some surgeon or other health care provider somewhere that disagrees with me. If you want to know what your surgeon thinks, then ask him or her. Check out my blog.
If I had to choose between the two, I would choose carbonyl, but I wouldn't choose either. I'd choose amino acid chelate. I supplement my multivitamin with a chelated Iron supplement from Vita4Life. It's worked wonders for my ferritin levels and I wish I'd found it sooner. http://www.amazon.com/Vita4life-Iron-Support-40-Capsules/dp/ B008A0YFHQ/