First off, they have a few very good brews. Their Belgian IPA is actually very good (not widely brewed in the area) and their Marzen is a solid interpretation. Gordon Biersch has become pretty big in Las Vegas and they sell by the cases in many stores so it is much more than a restaurant. Still I like a good beer and can respect their recipe for a few types.
Now we move on to the food side of the company. I went for lunch a few months ago. The best part of the meal was the complimentary taster of their Belgian IPA (as mentioned before, delicious). I then had a chicken sandwich that tasted like any other sandwich at any other pub/restaurant.
I would definitely come back to Gordon Biersch because I like the vibe of the restaurant, they have some solid beer varieties, the beer is not too expensive, and they have TVs to watch some sports. Still, the food is not the magnet of this restaurant's appeal.