I've gone to Soi4 dozens pf times and always have a wonderful experience. The wait staff are attentive and friendly, the décor is modern, and romantic, the prices are lower than you might expect, but the real reason I keep going back is the food.
Everything on the menu is incredible. The satay skewers are wonderful. I've tried (and loved) the chicken, beef, eggplant, and squid. I should mention the Indian flat bread, a fresh naan style flatbread that comes with fresh tomato, eggplant, bell peppers all covered in a sweet spicy curry sauce. I order this dish every time. As far as main courses, we've had some great fish, the beef dishes are great, and I still dream about the red-curry-honey-roasted-duck-with-pineapples. Be sure to save room for dessert, because they've got some incredible offerings, including a sweet sticky rice with mango, and fresh berries and Chambord over vanilla ice-cream.
Pros: Romantic, Reasonable Prices, GREAT FOOD
Cons: usually a wait, parking is tough