Siam Terrace is probably second for Thai food in CU. And even then it's pretty close. Both restaurants have their particular strengths so part of it depends on what you're in the mood for. The staff is very friendly although sometimes a little slow if it gets busy. I think they have the best pad thai in town. To me it has the perfect blend of sweetness, nutiness and spice complimented by the fresh bite of the cilantro and crunch of sprouts and shredded carrot. It's sweeter than your typical pad thai but it's very well balanced overall.
Their appetizers are nicely priced and I have enjoyed all of them that I tried. I would not recommend the Thom Kha soup here. It's a bit too sweet and lacks some of the depth of other versions of this soup I've had. It's not bad by any means, but it wasn't what I was looking for in that soup. Be bold with spice here. It can vary, but I find that they tend to be a bit more gentle with the spice overall.
A big plus for Siam Terrace is its selection of sushi. It's decently priced for the most part and everything I've had is tasty. I'd definitely recommend their Bakery sushi. It's moderately priced and is battered and served with some excellent eel sauce. Be careful when you first get it though as it's VERY hot.
For a drink, I recommend trying the coconut juice or Thai Iced Tea. Both are refreshing and a great, sweet compliment to the spicier dishes.