From what I've seen (though admittedly, I've played CS much less), there's a vast number of differences that can be listed -- Sindome is really stand-alone. Where CyberSphere possesses a more cyber-grunge feel, Sindome extends beyond that; the code is more robust (though there are some CS commands/conventions I like more), there's a bit more player-driven story (not that it can be helped, CS just doesn't have the same numbers), and it's harder to live comfortably in Sindome without engaging in RP to find opportunities to earn that sweet, sweet chyen.
I had a big Pro/Con list at one point after someone came to CS and started complaining it wasn't as good as Sindome, but I've managed to lose it somewhere. The easiest way to find the differences is really more to play; basically, it just feels different when you play it, in the long-run.
Hope to see you on-grid in the future!