Ouch. However, take this all with a few grains of salt (and not just the one's in Sage's wounds). Take Acumatica for instance. I can believe it is up there on the usability scale, but I find it completely impossible to believe that it has more functionality than GP, NAV or B1 let alone X3. Although I am certain it is on the upward trend, it is my understanding that it, as any other relatively new ERP, still has functionality gaps that need to be filled in order to be as functional as the competition like Sage 100 which isn't even on the chart (hmmm). If it were on an equal functionality footing (out of the box) I would be surprised.
I was also surprised to see Syteline as so easy to use. From customers who migrated off of it to B1 tell me it is about the same as B1and JDE being near the top of the usability scale must mean it has changed a ton since I last saw it. Usable for the functionality perhaps, but easier to use than all but 2 is surprising.