A breath of fresh air

Let me start off by saying that this pack is not for everyone. If you're looking for intense boss fights, dungeon exploration, and looting, then don't bother. For automation enthusiasts though, this is a wonderful experience!

what the pack is about

This pack revolves around the idea of accessing new dimensions with each stage of progression, and extending your automation capabilities with resources obtained from said dimensions. A concept that feels fresh, and is very well executed!
There's also an underlying story. It's not super complex, but it's a fun addition, and it ties the elements of progression together.

design choices

The pack is minimalist by design - there are no unnecessary mods, and a lot of recipes have been disabled to force players to approach problems in creative ways. A great example is how Botania's mana generation was completely redesigned for the purpose of this pack. A bonus of this approach is that the pack runs very smoothly. I've built some questionably efficient setups, loaded many chunks, and had no problems with lag or TPS.
Another thing this pack does really well: usually when you get started with a mod, you're forced to use tedious or inefficient methods to obtain resources related to it. What's great is that later on, you usually get access to a far more efficient method of obtaining those resources. It's a pattern throughout the whole pack, and it feels rewarding every time.
Playing this pack feels very much like a curated experience, and you can see the effort put into its development at every step of the way, right up to the end.
What really surprised me was the receptiveness to feedback from the modpack author. Every issue I've had with the pack, or idea I've proposed, has at least been considered by the author. I don't think I've ever encountered such a level of engagement with the community before.

issues

The only issue I have with this pack is the endgame (and this is the reason for 4.5, not 5, stars). It just felt slow and grindy. The pace really drops in the last chapter of the pack, and if you didn't anticipate the huge need to scale up, you might be forced to AFK. That being said, there is nothing in the endgame that "just appears out of nowhere." What I mean by that is: for every resource you need in large quantities at the end, you should already have at least a basic setup for it. There are no sudden new mods you need to interact with - you just need more of everything you've already been doing, and I think that's a great approach.

One final note: this is a 1.12.2 modpack, so if you're like me, you might miss some features from mods in newer Minecraft versions (especially modern AE2 features).