Our first trip to Sicily a few years ago was a stop in Taormina. It's a much better choice for first timers with its amazing views from the Greek/Roman Theater of Mount Etna and the sea. The town is small with shops and restaurants lining the hilly streets. In one shop we bought a kitchen clock that some Sicilian potter had made with a ring of colorful fruit painted on it.
Messina on the other hand has over a quarter million people and is an industrial center. The strait of Messina separates the mainland of Italy from Sicily and narrows to just 1.9 miles at its narrowest. A bridge between Sicily and the mainland that has been talked about since Roman times is supposedly going to be built now at a cost of over 6 billion Euros. If built it will become the largest suspension bridge in the world.The earthquake of 1908 and resulting tsunami destroyed much of the city so the architecture is mostly newer although the history of Messina goes back to the 8th century when the Greeks had a colony there.
The Duomo, erected in the 12th century, has been restored as have some other historic buildings. The Duomo had to be almost completely rebuilt after WWII as heavy Allied bombings destroyed much of the city and started a fire in the cathedral.
The city has a light rail system that went live in 2003 with the rails lined with colorful date palm trees.