The biggest difference between the two packages is memory adressing. In RSLogix you set up your own memory map, with N for integers, B for bits, etc. In the ADC DirectSoft the memory is pre-assigned, and you merely use it up as you go along. For example, V registers correspond to N files, C for internal coils and contacts correspond to B files, X inputs correspond to I: etc.
The AB has the advantage of allowing you to organize your variables in logically linked groups. To do the same in DirectSoft requires a llittle planning - for example V3000 to V3300 setpoints, V3500 to V3700 calculated engineerin units, C100 to C177 for alarms, etc. In many ways the DirectSoft is simpler, since you don't have to create files, but it is different.
The other big difference is Octal adressing. Your coils, for example, are C1,C2,C3,C4,C5,C6,C7,C10.
Having used both packages I would call them equal. The RSLogix is more powerful in some ways, but the DirectSoft is more intuitive and easier to learn.