The Kookaburra and Schiffer sets are basically the same, but there are some significant differences:
Kookaburra:
- Includes four extra chapters:
Vol 1: Fighter Aircraft of the German Luftwaffe; Organization and Victory Awards; The Aircraft Compared
Vol 2: Combat Stories
- Includes an index of illustrations in each volume, which is handy for reference purposes.
- Lower quality paper, with lower-resolution and lighter photo reproduction.
- Includes some photos not in the Schiffer set.
Schiffer:
- Heavier and glossier paper, with clearer and darker photo reproduction.
- Includes many photos not in the Kookaburra set.
- Some corrections to the Victory List.
It's worth having both sets, but if I had to choose just one, I would go with the Schiffer volumes because of their expanded pictorial content and superior photo quality.
Hope that helps,
Leon Venter