When I commented that I use my Tubus rack for heavy loads and the AddIt for light to medium loads, I did not mean to imply that the AddIt is not very strong. The heaviest load I have carried included two weeks of food. Thus, in my case, heavy was really heavy. And a lot of that specific trip was on rough roads that can put a lot of additional stress on the bike and racks.

The Tubus Logo is rated at 40 kg, the AddIt is rated at 30 kg. So, yes I concur that the AddIt is pretty strong, most people would never put over 30 kg on the back rack. Plus for most people, touring is done on well paved roads or good quality gravel trails like the rails to trails routes where a 30 kg capable rack would work great for almost everyone.