I have not compared to la Scala Optologic but I had the S2 and upgraded to the S3 last year. To my ear, it's a very noticable overall improvement in terms of level of transparent and music dynamic. However, I felt that between the S2 & S3, they are also somewhat "different" sounding. S2 is more laid-back and warmer sounding DAC while S3 is a cleaner (compartively speaking) with more details and punch DAC. Overall, I'm loving my S3.
