I lived in Luang Prabang from 2013 to early 2014, but visited Vientiane many times. My advice is to skip VTE though, if you find yourself there, you can certainly make it enjoyable.

If anyone here is a Chase Sapphire cardholder, you can read the Luang Prabang travel guides I wrote for them/AFAR Magazine (Login required – the link takes you to the "Overview" slideshow, but there are another three guides listed below it with more detail on LP's culture, food, and sights)

Hope you enjoy your trip! :-)