I had a client with that earlier this year. Original return efiled without the dependent in April, with paper-filed 1040X mailed at the same time. Identity theft issue finally completely resolved in August. Amended return claiming the dependent efiled uneventfully in September, when the paper 1040X had still not been processed.

So so so much faster and easier than paper filing. I think the client put in a lot of hours on the identity theft issue, though - I know both taxpayer and dependent had to travel about 90 minutes each way to appear in person with documents proving their identity.