Reviews for this place were really mixed so I thought I'd take a chance. Don't think I'll be back.
Vientiane Palace bills itself as "Lao-Thai food" so the menu is different from your standard Thai restaurant, which makes it interesting. If you go here for a greasy gut-bomb guilty pleasure, you might be happy. But I like my vegetables fresh and well seasoned, not drowning in oil. (Seriously, I think I might have heard them crying out for help.)
I asked to get my food spicy (3 out of 4 stars on their scale) and it was decently spicy but I bet I could have withstood the "extra hot" ... If you like heat, go for the 4 stars. On the other hand, you could also do this at home: I tend to suspect that the reviewer was right who claimed this restaurant achieves its spice level by adding more siriracha sauce.
Portions also weren't great for the price. $22 for two entrees. Our "half chili duck" was actually delicious... Greasy but well flavored... However, the container was at least half bones. Our other dish, curry squash with chicken, had hardly any chicken.
Onward in my quest for excellent Thai food in Madison.