I recently upgraded my S1 to S3 and couldn't be happier.
Just curious, what would you say are the biggest improvements?
Is it just deeper and more powerful bass?
How would you compare the mid-range?
I love the tight and super clean bass of the S1, but realize it definitely has its limits with respect to depth and output. Since my room is smallish, I wouldn't personally upgrade just for the bass, but if the mid-range is better, that would be different :)