Chris definitely isnt more powerful.
Chris is smooth, and has a very consistant forehand with heavy topspin, but has a terrible second serve.
Ian is very smooth, hits flatter groundies with less margin, and has a much stronger backhand. Ian didn't serve great today, atleast I was expecting a bigger serve, but I still would give him the edge in the serve column, on his serve today.
Chris Williams might be able to fight and take a set, but Ian has played in many more big matches than Chris has, and he will come up with the goods when he needs them.