Firstly, may I add that it is interesting to note how popular slide software is becoming.
We have modelled mass concrete, gabion, soldier pile walls and have got fairly good outputs from slide that we checked against hand calculations. The results were not far off depending on the mechanism of failure you were looking for.
When it comes to other wall systems like stacker block (dry block) walls we tend to stick to the manufacturers software that is provided to give us a stab at the preliminary design.