I have never played however I may get the starter set and be a keeper. My questions are sort of related to Grahams post
4-6 players 1 shot? Can the starter sets handle that many players. Ive watched some lets plays and I'm not sure
after that best 4-6 campaigns
Yes, absolutely. I agree with
@overgeeked that 3-5 works best, but if you have 6 and need to play with that many, I'd just go with it and expect things to be a littler easier. Also agree with the ease of converting older scenarios. I don't even keep mine sorted by edition -- there's too little difference to worry over.
in many ways this game seems to work for non gamers as seems to be less complicated than 5e D&D
At its core, it is a relatively simple system. The latest version (v7) adds some complexity to the combat rules which I quite like, but honestly, feel free to ignore it until you want to add those rules in. For comparable activities, rules are lighter than 5E. However, there are a fair number of extra rules -- sanity, luck, learning spells etc. that are more complex. The good news is that the system is pretty resilient to getting them wrong -- it's mostly a matter of "oh, you should have been penalized for that" or "it should have taken you 4 weeks, not 4 hours to read that tome". Nothing game-breaking. I have been there often ...
The trickiest thing for players and GM is to agree on a tone. It is a horror game, and that is hard. Fantasy is all about feeling powerful -- easy to GM as players level and get stuff that makes them more godlike. CoC is not.
@overgeeked characterizes it as a downward trajectory game, and that is definitely one way to play the game -- probably the most common. For one shots it is the most fun, definitely and works well for short campaigns. For longer campaigns though you need as GM to decide how you are going to run it. I ran
Masks of Nyarlathotep in that style -- people lost characters to insanity and death, and even the survivors were badly broken. It had that "how long can you survive" feel to it. In contrast I ran
Beyond the Mountains of Madness for 20+ sessions, and it had the same characters until the epilogue. Sanity went down, but I gave plenty of opportunity to increase it, and mechanical horror checks were rarely more than once a session (with notable exceptions). If you play in a style where, at the end of an adventure, you can say "defeating the horror gives you a feeling of relief as you make the Bay Area safe again for mankind -- restore 6 sanity points" or if you allow the regaining of sanity by mental health intervention, you can keep going infinitely long.
Having said that -- as soon a player gets access to magic they are doomed. It's too much fun not to use and it absolutely will drive you insane faster than anything else in the game (expect great old ones). And the joy is -- the players will do it to themselves. There's a well established rule in CoC GMing -- if you want to kill the player, give them guns. Because then they'll fight instead of running, and when they go insane, they don't just punch their friends, they unload a shotgun into the backs of their heads. I'd also add that if you want to drive them insane, give them a spell book.
CoC is an odd bird -- I don't generally like old systems as RPG systems have so much improved over time. But the mix of simplicity at heart with special cases and few byzantine rules definitely appeals to me. It's still my go-to for horror gaming.