Unless you are willing to spend a good bit of money and don't mind pushy Chinese, I wouldn't recommend the casinos. Definitely not for the casual gamer. Very few slots and all the tables have high buy-ins. The only "cheap" table (aka a buy in under 30-50$) is roulette.
I have been to both Gangnam and Walker Hill casinos. Both same. Walker Hill had a nice free buffet actually. I am sure Gangnam does as well, just didn't see it.