I'm not sure I can answer the how different was he question for you. Certainly others were interested in similar questions, be they optical, alchemical or astronomical/mechanical. Afterall it was only after prodding by his contemporaries that Newton ultimately looked at the question of what sort of orbit a body would take due to an inverse squared force. Certainly his mathematical ability was unique and it helped him pioneer new ground and solve problems that people like Hooke were woefully ill-equipped to approach. I'd personally point to the methodological approach in the Principia as his single greatest departure from the natural philosophy of the time, as well as his most lasting legacy, particularly among the so-called 18th century Newtonians. The fairly biting objections raised from followers of the mechanical philosophy on the continent also give some indication of exactly how different his approach really was (although some have characterized it as something of a throw-back to prior "occult" philosophies). Reading Newton's laws of reasoning really doesn't give you much insight into his methods, and it's not as if all Newton scholars agree on exactly what his methodology was, but personally I'm inclined to side with G. Smith's view. It's a bit complicated but if you're interested I'd pick up a copy of the Cambridge Companion guide to Newton (Smith is also an editor) and read his essay "Newton's Method." You could crudely describe it as moving from phenomena to a mathematically characterized force and then to a physically characterized force that accounts for the specific phenomena. Shapiro's piece in there about Newton's optical work might also be of interest.

There's really so much to say here but perhaps this will be enough to convince you of his central importance in the history of physics.