Have got a Howling Moon with awning on my Disco.
Have used them in Africa and Europe with lots of success.
Have to bear in mind that once its up you can't move the vehicle.
The weight is not inconsiderable, a lot more body roll.
I have up rated the suspension to cope with the increase in load, its a bit harsh when the tent is not fitted. I generally take the tent and rack off for the winter.
Lots of different types around, depends how much you are going to use it and in what weather.
If you want to look at sometime let me know, it will be back on for Easter.
Coop