Just wrote this elsewhere:
Wow, this is goooood. Picked it up on Friday, put about 15 hours into it over the weekend (across a single player and a multi-player map.) I am very impressed.
Comparisons to Factorio
It's interesting how not like Factorio it is, in a funny way. It's significantly simpler, at least in the parts we've played (we're through to steel, which I think is a bit over halfway through the current content.) But still plenty deep enough to drive you mad figuring out optimum production chains and ratios. It does some smart things to streamline the Factorio experience without losing the core essence. For example, instead of modules (with a complex production chain to make them), you get the ability to "overclock" buildings with a slider. The slider scales building production rate linearly, but scales power consumption exponentially. So there's an interesting iterative tweak process to find the optimum place somewhere in the middle. Also, you spend less time feeling like you are fighting the game, eg. inventory sizes are much more generous (obv unlocking inventory size upgrades in Factorio is A Thing and I get that.)
I've been telling people it's sort of like the Forza Horizon to Factorio's Project CARS. The latter is the brutal, no-holds-barred simulation. The former is the more approachable and gentler intro, but still with plenty of stuff there to get you hooked in. Satisfactory is also a bit more of a structured game and less of a sandbox, which might make it easier for some people to get into.
Also, aesthetics are a whole other thing when you can build in 3d and make buildings around your factory production chains and paint them different colours. On the other hand, the belt spaghetti you can make in 3d is truly incredible / horrifying.
The core gameplay loop is the same in both games, though. Anytime you look at your factory, you can probably immediately identify half a dozen things that could be improved: this assembler isn't running at full efficiency, there's not enough of a particular resource being mined, this part of the factory is just ugly and should be tidied up, the next tech tier unlock just needs 15 more of some widget to be made. The game's interface makes re-shuffling things around easy so any given improvement is probably only 5-10 minutes away from being done. Then it's on to the next improvement, and the next improvement, and the next, and oh it's dark outside now.
Early access stuff
Honestly it doesn't really feel like an early access game. I saw a few bugs but mostly clipping or floating object ones; no worse than any launch day Bethesda RPG. There are reports of connectivity issues with MP games which we haven't seen. Also, there's plenty of content here already, even for Factorio veterans like us who probably rattle through it a little faster than people new to factory games because the concepts aren't new to us. I'm often dubious about early access games but this one seems like a solid choice.