Appearance-wise, he's quite handsome, and his jacket add a cool touch to his simple, yet attractive design. And I'm such a sucker for those kind of unrealistic anime fro.
Personality-wise, we all know nothing about him. But it's reasonable to presume that he will have a rather smug personality. Over-confident, but not too arrogant to the point of jerkassery like Gary. A rivalry relationship wil blossomed between you and him, but doesn't harbor the kind of bitterness Silver and Ethan had. And he definitely seems more mature than Barry and Bianca.
And I heard somewhere that he's very protective of his sister, and willing to do anything for her...Very interested in the direction this is going.