They are both great brands, but if you prefer the ingredients in Acana it should be fine. Just check Calcium and Phosphorus levels, the last time I checked there were some of their formulas that were a little higher than I like to see for a growing GSD. At seven months it may not be as big a concern, but they are still growing for a while yet at 7 months.
Omen v Wolfstraum
Jasmine Katie v Doolanshaus