Starting with 4.0.6 and upgrading as they come out, I've been able to play 3 out of 3 full games with no serious issues.

[Obblera]

Started at 4.0.6, upgraded as patches came out.

Played 3 full games with hive mind, out of 3 attempts.

I'm happy that it "basically works" now.

Only problem I have had is the Elder Woidwurm keeps getting stuck.

Also I now understand 4.0 planets, so yay.

There is a lot of balance tuning to go, e.g. the number of idle drones on planets, but no crashes, nothing that broke a save, nothing that changed the outcome of a run, etc.

edit: Can't really comment on speed. It seems comparable to the old game, which was always playable for me, as I use a high end CPU. So I am not the best person to ask for this. (Alder Lake which has good single core perf. Also use Apple M3 but it has problems with Stellaris, though that's probably not a Paradox thing)

 

[WJJellO]

4.0.10 feels noticeably more responsive than 4.0.6, which is nice. I'm on a computer that is never resource-bound while playing the game (i.e. any bottlenecks are a reuslt of the game not actually using the compute available to it), so I'm probably not in a good position to comment on performance other than "if I notice it, it's really bad."

The state of the game itself.... eeeeeeeeeeh. Mostly due to very poor AI decision making. But on single player it's at least playable.

 

[Dexev]

I mean that's great for you but it just depends what you pick to play. The last three builds I've tried are fundamentally broken.

Slavery doesn't work. Slaves wont take the jobs off normal pops and resource bonuses don't apply anywhere.
Necrphage has been destroyed by the patch and their purge is still bugged.
Cybernetic creed can't even colonise their planets.

I've played a bit with some of the builds going around that do work - crowdsourcing/parlimentary system/civil education stuff. If you can call things being absurdly overpowered in combination with the AI struggling 'working'.

I know Devs are trying here but there's a long way to go yet. Feel like giving up on trying to play at the moment. Cool ideas and content are nice and all, but a buggy unbalanced mess is not fun.