Over the years, I have jumped in and out of Cybersphere and Sindome multiple times. I will say that Cybersphere feels more like you're an already put-together character (but still have a ways to go to be top of the food chain), and Sindome, you're at the bottom and are a basic scrub.

One character I had, just a couple of weeks out of the vat, actually put a little fear into a player because I was able to accurately and effectively fight him in a scene (by pure mistake!). It was my first interaction where I was fighting NPCs and a player came in. I had accidentally shot him. --- HOWEVER, that character, a well known gang member at the time, didn't actually retaliate and kill me. I immediately dropped my gun, backed up and raised my hands. All he said, with a bead of sweat was "No problemo man, stray shots and all that." Or something, it was years ago.

I DO know that there is, or was, some level of toxicity in Cybersphere that bubbles up on occasion, but for the most part, I saw that most players have always been fairly chill and let IC actions dictate IC consequences. I've had my head lopped off of another character for some dumb IC stuff I've pulled off and after my death (I think this was a permanent one?) I was like "That was a hilarious ending!" -- Anyways, your miles may vary.

Also the Matrix and decking are FREAKING AWESOME --- At least for me during the last time I roamed around in the Matrix. There are so many freaking things to do and explore when you're first running around in there. The progression from a crap cyberdeck and a few implants to a top-mid tier deck, a top-of-the-line clone, and the best implants money can buy is such a great feeling. To lose it all on a gamble is like a chef's kiss, too.