It depends on the quality of the blade. In theory, razor blades should not be jagged like an X-acto blade. Still, neither is going to cut as well as a proper surgical scalpel.
Be careful with a proper scalpel- you can't hack and slash like one can with a razor blade or x-acto or utility knife. It will cut deeper than expected.
Angle of the blade matters a lot less with a scalpel- while you may be able to slash while holding it at an angle with another blade to keep one's self from cutting too deep, you may not find that you have the same control with a scalpel.
I've been a life long cutter- and I can say that the transition to scalpels was not good for me. I have done far more harm with them.
Be careful.