I've got mostly positive, but mixed feelings with this update. It's a little pricy, but came at a conjunction with a major update overhaul which came with some very nice free features. I'll lump them all into this review.
Pros:
-New megastructures, which add some exceptional benefits, and give new aims to shoot for. With the new changes, I am grateful for a way to get lots of minerals.
-Expanded economy. Lots of important decisions to make, which greatly expand gameplay.
-The Acrology Project. Allows you to turn worlds into city worlds, with unique speciality districts.
-Slaving overhaul. Great with the Apocolypse update. Allows you to create Thrall worlds for breeding slaves, which you can then sell on the intergalactic market.
-Planet specialities. Having planets devoted to a single sector will grant them a bonus.
Cons:
-Megacorps are underwhelming. It's not like the other special authorities (hive mind & machine intelligence). It allows you to build special building types on other planets, which is fun at first. But there isn't much else that sets them apart.
-You need MUCH more management. It becomes plenty difficult to manage more than 4-6 planets at a time. Plus, population is now continually growing, and must be actively watched and managed more than ever before.
-Habitats and ringworlds have largely become obsolete. There is no reason to have any of them, especially with Acrologies.
-Carivaneers were funny in how they poke fun at loot boxes. But they're a joke which gets old very quick. I destroy them the moment I get the chance, so they'll stop annoying me.
-Hybrid pops. They can show up randomly when a caravan leaves your system, or you research the right ascension. Sounds cool in practice, but you'll end up with a gazillion different species in your empire
TL;DR. I love the expansion and the update, no regrets. It is overpriced. A lot of the stuff I won't use. But I am happy to have it.