In the context of illegal/recreational usage, not really. Chemically they are similar, and affect the body in pretty much an identical way. Methamphetamine metabolizes to amphetamine. Methamphetamine has more potent effects for the same dose. And of course street meth is a crap-shoot.

Yes, really. That methyl group makes a big difference. It increases potency, toxicity, absorption rate and overall addictiveness, hence why amph is commonly prescribed, while meth (desoxyn) is reserved for severe narcolepsy.