I tested the stem separation and S 1 V7 it is compared to Logic very bad. I used a track by Stereolab "Baby Lulu" and in S 1 are tons of brass in the vocal part, the bass has no attack an is probably in the also blurry drum part. The other track is thin and no bottom end in the guitar.
All in all it is Logic much tighter in all parts and S 1 totally mushy with all stems and not really "intellegent"