Had a river view room on the second floor. It overlooks a dirty ditchlike river. The actual river is obscured by a row of bungalows, two bars and some bushes. The view of the mountains, however, is magnificent. The room was very clean with no bugs. The bathroom was a good size but dark. The shower head was handheld with no mount. The TV had good channels although all the ones up til about 90 do not work.
Noise will be a factor. The "Bucket Bar" across from you will blare music til about 3am. Drunk kids will run up and down the halls around the same time. You should know this going in since you're in Vang Vieng so you really shouldn't complain about it.
The upside really is the size of the room, the cleanliness, and the view of the mountains from your french windows leading out to your balcony.