SnS helps me when I need to quickly sketch out some page-specific CSS or JS ideas and I don't want to go do the FTP dance (I use Headway). It's also perfect for doctoring websites for potential clients - I just install SnS, slap some jQuery in there, and I can make fixes on even the most busted, poorly built sites.
It's also nice to have syntax highlighting within the WP Dashboard. Just feels good. And I can put my CSS reset styles in here while I build, to keep it out of the way of my other CSS.
I don't know if I've fully tapped the power of SnS - perhaps I'm missing some of its best features. Is there a codex?
Anyway, fantastic job.
Dave Bloom, Ginger Soul Records