Hi,
the Planet Bike rack works just like the other racks. It's both lighter and cheaper.
It's not as rugged; but I have used even lighter racks for years with no problem.
If you are going on expedition tours; by all means get an expedition rack. Me, I like light and cheap. 3 of our 4 bikes have the Planet Bike rack so we can swap panniers. The fourth one is even lighter, and less rugged. I have had almost everyhing on a bike die on me. Frames brake, stuff wears out. Never had a busted rack. A decade ago I was using a cheap wimpy (but very light) Nashbar rack. I managed to lose their odd mounting hardware; but they are still kicking around,
ready to go if I ever figure out a way to use them.