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!
Anyway, I haven't played CyberSphere but based on what I have heard, both about its current state and about the Sindome origins back when the split happened, Sindome is very very much about roleplaying in-character and CyberSphere is much less so. Second hand impression, not first hand knowledge.
The Lore and Wiki parts of the Sindome website can give you lots of peek into the IC history and culture. The fact that specific details about game mechanics, gear attributes, and commands for exercising specific skills are not present on the website should show you that Sindome is immersive and the way to learn those things is through actually playing.
I've seen CyberSphere's website and they give away tons of information which we here would expect players to learn ICly. We also have a rule against sharing IC information in any OOC way, which also is contrary to what I've seen in CyberSphere's forums: The posting of roleplaying logs.
I still finding new things to do every single time I walk outside. There's literally so much code, and so many different characters to RP with. Every time I think I'm starting to get a hang of things, someone shows me a whole new location to explore, a whole new dynamic to try out, a new situation that will push the limits of my imagination and challenge me with new way to deal with the ever changing shit-storm of happening around me. If you're really missing decking, it's because you're not focused enough on the million other things you can do.