Normally I prefer to beat a game before providing feedback, as it's hard to see how everything will play out in the parts I haven't reached yet. But my schedule this month means I probably won't be able to finish until after the 1.0 release, and by then it won't really matter anymore. I don't know if you'll find these comments useful. Maybe you will, maybe you won't.
So keep in mind this is from an early-to-mid game perspective. We've just unlocked the steel age and are setting up steel smelting. Gold and oil are on the to-do list. Only red and green science have been automated, no military or blue technologies yet. The base is in the middle of being upgraded from burners to electric, and we're in the process of setting up iron intermediates instead of the hacky "we need a bunch of chassis five minutes ago".
I'm also a big fan of "figure it out as you go, learn how to do it better next time," so this base is inefficient (way too many lower-tier basics, too many burner inserters that need manual attention) since I spend my time building the new stuff instead of ripping up and perfecting the old.
As much of the base as I could fit in one picture: https://imgur.com/a/4JQBeBW
I don't necessarily mind the newer tiers rendering the older tiers obsolete, but it does make some of the early-game intermediates feel wasteful. There's simply less to build with each type compared to iron, and the base is small at the start so the quantity of drills and production machines and turrets is much less than later in the game. For some reason I thought we'd need reinforced bronze plate more, but there's 4000 of it idling in a chest somewhere. Oops.
I don't think I'd go through the effort of automating the lower tier intermediates. For example, large/small copper/bronze chassis. It'd be "good enough" to automate the basic components (rivets, rods, beams, plates), and hand-craft the last few steps. Same with copper and bronze pistons, both of which are used in like two recipes - one you build a lot of (the crusher), and one you build pretty much once (the generator). In contrast, iron pistons are used in all kinds of things and you're going to build a bunch of them, so it's worth the effort of an assembly line to set up iron intermediates. The copper and bronze capped beams also just feel like an extra step on top of the wooden beams and I keep forgetting they're a thing until needing to build something that uses 60 of them.
Some of these opinions might change as we play more. I thought copper bearings had limited use, until I found out we're going to need them for gray science. I can't quite tell how much copper cable I'll need in the future.
The burner phase was a nice touch. Factory patterns set up for electric pole spacing don't work as well in the burner phase, so a better base would use more custom layouts. We figured that out in the last third of the burner phase, which is why the pictured base layout isn't very good. Unfortunately, the parts where I had inserters feeding inserters got torn down when we moved the rubber production and replaced the copper labs.
I liked the option to use crushed ore for walking paths. I am assuming nothing was added that might set all that coal in the ground ablaze.
Punkbots also helped, though don't use them to deconstruct items that have 100 coal inside or it'll take forever.
The monowheel was also a really nice addition. We're just under 15 hours in, but I spent probably a full hour driving around trying to map out the edges of the massive lake next to the base. It also combos well with the early-game shotgun. Drive headfirst into a mass of biters, hop out while it runs over a few, and blast away. (Please don't take away wood as a fuel. In the event I lose my original monowheel and all its stored coal from an unfortunately placed rock trap, wood serves as a nice contingency fuel supply to get back home.)
I thought I would like the display plates more. I can see you put a lot of effort into making a bunch of high-res icons for them, they just didn't support the types of icons I was trying to use. Two examples are I wanted to mark the path that led to the wood production with a log, beam, or tree (especially since I believe you added the two sapling icons) so I could find it when driving around, and I don't think any of those were options for the display plate. The other case was I wanted to indicate where the belt supply chests were, but there wasn't a good choice for that either. Ended up going with the copper gear wheel since it was a major ingredient. Still, they are far better than the tiny odd-shaped Dectorio signs.
I did like the addition of the pollution filters. Vanilla doesn't offer many options for pollution management aside from "turn your base off", whereas here you get to choose between reduced pollution and one of the other modules. I'm looking forward to what this can bring to a Deathworld game after I finish this one.
I don't know if this was changed in a recent update, but a couple technologies unlocked components that weren't really used anywhere (bronze gears), and we couldn't figure out what the yellow ! on them (shown on the Bronze Age technology unlocks) meant, nor where they were in our inventory. I thought it meant an existing recipe got upgraded or something.
FNEI seems to have trouble searching. If I want to look up anything with multiple words it'll fail. I have to limit myself to one word (often the metal name) and pick from a list. Maybe it has something to do with the internal names of all the items. This may be a problem with FNEI and not IR specifically. I haven't used FNEI before, but there were just so many new intermediate products.
Overall, it's been a refreshing change of pace after playing hundreds of hours of vanilla and vanilla base style mods. Thank you for all the work you've put into this.