Rib racks are a must if you are doing food for a number of people - it is really the only way to get a large number of ribs on the smoker while still allowing for space between the ribs to get a good bark on them.
This is a slightly larger rib rack than the other one I have, and you can squeeze seven ribs on there depending on thickness, but perhaps it performs best with about five. The picture I have attached is me using both to get a total of 10 racks on the smoker.
The metal is solid and it seems like this will be sturdy enough to last a long time. They are not cheap so you do want something that will not break easily.