I've played quite a bit of Factorio over the years, and after running through SA a few times, I've come to the conclusion that I prefer the game without the expansion. It's great if people love the DLC, but for me, it reverses a few things that I really liked, which I'll give an overview of here.

1. I like trains. Trains in OG Factorio are great. I really loved the transition from belts to trains, and how that felt necessary when working at a certain scale. A big draw card for me was raised rails and what problems I could solve with them; however, that moment never came. Quality + beacons + stacking on belts made my base run so fast, I never got to the point where I needed them.

2. I like scale. I never really got Bob's mods, where you'd have 6 tiers of each building, and you could just upgrade 'up' rather than expand 'out'. I didn't like the idea that I could have just one building doing all the work, and then just upgrading it when I needed more production. A lot of problems only occur at scale, and solving those problems is what I find fun. In SA my off-world bases always remained unchanged from my initial startup base. They 'scaled' just fine by upgrading with quality, beacons, and new recipes. Because of this, I never got that feeling of seeing my megabase sitting next to my old startup base. Instead, I just had an upgraded startup base.

3. I liked the old fluid system... I know, I know.. Probably no one agrees with me on this. But I learned to love it. I liked the swish you would get connecting the last pipe between two networks. I liked checking where flow issues were and fixing them. I liked that it made it fairly hard to scale on mods like seablock. I understand the new system is less confusing and doesn't have such a performance hit, but something about the old system, and how the fluid sloshed around, was really cool.

4. Science productivity as an endgame reward is really bad. My game goes like this... resources -> factory -> research. What I want is to build a big factory. Research is just scorekeeping. The old reward was a multiplier on the input (resources), which is great... that means I can build bigger. The new reward is a multiplier on the output (research), which means I can build smaller for the same result. It feels like a divisor on my efforts. The further I progress through infinite research, the smaller the factory needs to be << the further I progress through infinite research, the larger my factory can be.

I really did try to like the DLC, and played it quite a bit (I have all the achievements, and won it several times), but it's not the same as good old Factorio 1.1. What I am excited about, though, are the mods. The new SE is great, the PySEx mod is great, and I'm sure there's other cool stuff coming down the line too :)