Reagan was absolutely a professional politician and a very smooth one at that. He also was very principled and while he compromised where he had to he stuck to those principles closely.
Trump is a different beast. He is definitely not a professional and probably the least politically experienced president in our history. He also does not appear to have any consistent political ideology, but one important principle. That principle seems to be he promised to do a certain set of actions and he is committed to fulfilling those promises to the best of his abilities. He is also crazy like a fox and seems to be a master of misdirection who keeps his opponents guessing about what he will do next.
Reagan was a professional actor...He only spent a small portion of his life in elected politics...