They are very similar, but the euphoria with Adderall is significantly less than with meth or other speed you'd buy on the street. For some people meth might be an effective substitute, but I think most people would find the high and the side-effects too distracting. Plus, that euphoric high increases the likelihood of abuse and addiction.
I'd add that the people I've known who did a lot of meth tended to have physical health issues and looked like shit, which was not the case with the people I've know who abused Adderall.
I'd add that the people I've known who did a lot of meth tended to have physical health issues and looked like shit, which was not the case with the people I've know who abused Adderall.