St. Paul trip...Sole Cafe or Ngon Bistro?
I hope you find someone who has been to both.
I've been to Ngon many times. What you will find there are both traditional Vietnamese preparations and modern interpretations. Both are done very well. You will also find local microbrews and a decent wine list (if those are important). I've wanted to try Sole (drive by it everyday on my work commute), but haven't been yet.
Ngon has a better ambiance and a nice beer list. Both have excellent food, but Korean and Vietnamese food is quite different. Ngon also has other options like steak and pasta, although I usually stick with the Vietnamese food when I go. I think you can't really go wrong with either of them.
Sole Cafe has better food (some of the best in the Cities, IMO), but an awful alcohol offering. Ngon has a great beer selection, but some mediocre food items, though the pho and rabbit dumpling are really excellent.
And yes, they are two different cuisines, though both make an effort to elevate their food beyond typical local fare.