I live in Laos for a good 16 years now. Have lived in the Luang Prabang, Pakse and now Vientiane.
It's an easy country to live in if you have your connections helping you with the paperwork.
I know there are different opinions, but I think for the average expat, Vientiane is by far the best place to live. Most people just see the fairly compact city centre, but Vientiane is quite spread out.
What to like: Best nightlife, best food choices, best healthcare options of Laos, while still being Lao city. Plenty of cheap accommodation available. Because of it's size (around 1 million people) there's plenty of choice in what kind of people or places you want to meet/be or avoid while still having a social life.
What not to like: Traffic can be annoying (but it's no Bangkok) and limited public transportation options. Loads of big cars blocking the sidewalks when parked.
Luang Prabang is a great town but most expats stay there for a year or 2 and then leave. The centre is touristy but pretty. If I ever would go back to stay, it would not be in the centre.
If you are a bit social you will end always meeting the same people, which can be good or bad. In high season the roads are blocked by pesky minivans.
The south of Laos. Less tourists, more locals. The south feels different than the north. Maybe because it's closer to Cambodia. Lots of nice things to do and if you have a good job or your own business, can be a good place to live. The cities of Pakse and Savannakhet offer more convenience than Luang Prabang, but with less tourists.
All in all Laos is of course the more quiet option of mainland SEA. Still has plenty on offer though and the country is more modern than you would think.
I can pay almost everything with my banking app, internet and mobile connections are good in the populated areas. (5G in the capital)
If you live in Thailand and miss the convenience of shopping or eat at international franchise, that yes, there are 7-11, Mini Big C (also a Big C), Amazon Coffee, PTT, Pizza Company, Swensens, Dairy Queen, etc, etc. in the capital and some in the rest of Laos. Roads can be great or absolutely atrocious, even in Vientiane. Chinese influence is quite big on the country now, and that is good and bad.
Cheers.