Hello and welcome to the forum!
The Sam Sand Dunes and the Khuri Dunes are more or less the same when it comes to appearance. There's little vegetation and has amazing views of the desert. They are just about the same distance away from Jaisalmer but on different directions. So when it comes to distance, there's no difference as well.
The difference lies in the commercialisation aspect. Of course, the Sam Sand Dunes are more popular and touristy. An advantage of visiting the Sam Sand Dunes is that there's plenty of accommodations and other attractions in the area. Public bathrooms are easily accessible as well. Along with that comes the disadvantage of trash, rubbish and crowds.
The Khuri Dunes are less commercialised and hence, less tourists come here. The advantage is that there's less crowds and the place is more peaceful. It has lesser activities, attractions and accommodations but still, you can find a few here. Public bathrooms might be harder to find here.
So depending on your interests, you can choose either one. If you like serenity and peace, go for Khuri Dunes. If you like activities and convenience, go for Sam Sand Dunes.
I hope this helps!
