So I've played two games so far while using the 2.2.2 beta patch: one synthetic ascension as a fanatic materialist xenophile playthrough, one rogue servitor playthrough.
Synthetic Playthrough
I can't speak to how the synthetic ascension path stacks up against the other paths, but I can say that synthetic ascension works fine if you use it on an already mostly established empire. The build speed for robots isn't a problem because of all of the roboticist jobs produced by the capital buildings, you still get immortal leaders and 100% habitability, all of the leaders get the usual bonuses, and so on. While new colonies may be slow, by the time you have synthetic ascension you will probably be able to move them from your more established colonies to kickstart them (unless your empire is opposed to forced migration, I guess). I actually found I had way too many pops since my empire was relatively small and I had nowhere to put them all, though it's possible being a xenophile with a lot of immigrants was leading to overcrowding. Apparently everyone wanted to come to my empire and turn into robots.
Also, my economy did basically crash for a couple years after ascension. The issue of farms no longer becoming power buildings is pretty frustrating. It would probably be better if synthetic ascension took place gradually rather than all at once so you can account for the fact that your economy is going to require way less food and way more power. Luckily food was valuable in my playthrough, so I could sell it to make up for the power loss.
It's entirely possible synthetic ascension is now the weakest path — again, I don't know — but there's always a weakest ascension path and there are always less useful ascension perks. As long as synthetic ascension isn't literally worse than leaving them cyborgs, which as far as I can tell it's not, that's fine imo.
Rogue Servitor Playthrough
Oh man, this was devastating. These guys used to be my favorite playstyle, but they now feel basically unplayable, and not Stellaris meme unplayable — for real unplayable. Even at 50% growth speed, bio-trophies rapidly begin to grow faster than your machine pops, and keeping up with their needs is a losing proposition. Don't even think about conquering any planets, or you'll suddenly have a massive disparity in machine-to-bio-trophy ratio and it will crash your already fragile economy. Needing to keep up with robot upkeep and consumer goods cripples your mineral income, and good luck starting a colony. Even after years and years of waiting for them to grow enough pops for you to build a robot factory, the pop growth is atrocious.
Plus, without servitor morale, you only gain any sort of non-unity bonus from them in the form of stability, meaning you have to keep your bio-trophies on the same worlds as your machines to get any benefit from them, which means you can't really take advantage of the machines' 100% habitability or the machine world ascension perk. And don't sass me about lore and RP — if I want my robots to have high morale on a mining world knowing that their trophies are happy and safe on some gaia world elsewhere, I don't see why I cant. Remember that the drones are not individuals, they're all extensions of one AI; it doesn't really make sense that only the drones near the bio-trophies are performing better.
And speaking of the unity "bonus" you get from bio-pops, is it even advantageous? They certainly start out making a lot more than other empires, but it seems like they might actually fall behind on unity production due to their inability to make upgraded unity buildings. Maybe there's an upgrade to the bio-pops or the sanctuaries in the tech tree, I don't know, I had to quit the playthrough because achieving a stable economy was proving completely impossible as soon as I tried colonizing, let alone keeping up with the other empires.
Synthetic Playthrough
I can't speak to how the synthetic ascension path stacks up against the other paths, but I can say that synthetic ascension works fine if you use it on an already mostly established empire. The build speed for robots isn't a problem because of all of the roboticist jobs produced by the capital buildings, you still get immortal leaders and 100% habitability, all of the leaders get the usual bonuses, and so on. While new colonies may be slow, by the time you have synthetic ascension you will probably be able to move them from your more established colonies to kickstart them (unless your empire is opposed to forced migration, I guess). I actually found I had way too many pops since my empire was relatively small and I had nowhere to put them all, though it's possible being a xenophile with a lot of immigrants was leading to overcrowding. Apparently everyone wanted to come to my empire and turn into robots.
Also, my economy did basically crash for a couple years after ascension. The issue of farms no longer becoming power buildings is pretty frustrating. It would probably be better if synthetic ascension took place gradually rather than all at once so you can account for the fact that your economy is going to require way less food and way more power. Luckily food was valuable in my playthrough, so I could sell it to make up for the power loss.
It's entirely possible synthetic ascension is now the weakest path — again, I don't know — but there's always a weakest ascension path and there are always less useful ascension perks. As long as synthetic ascension isn't literally worse than leaving them cyborgs, which as far as I can tell it's not, that's fine imo.
Rogue Servitor Playthrough
Oh man, this was devastating. These guys used to be my favorite playstyle, but they now feel basically unplayable, and not Stellaris meme unplayable — for real unplayable. Even at 50% growth speed, bio-trophies rapidly begin to grow faster than your machine pops, and keeping up with their needs is a losing proposition. Don't even think about conquering any planets, or you'll suddenly have a massive disparity in machine-to-bio-trophy ratio and it will crash your already fragile economy. Needing to keep up with robot upkeep and consumer goods cripples your mineral income, and good luck starting a colony. Even after years and years of waiting for them to grow enough pops for you to build a robot factory, the pop growth is atrocious.
Plus, without servitor morale, you only gain any sort of non-unity bonus from them in the form of stability, meaning you have to keep your bio-trophies on the same worlds as your machines to get any benefit from them, which means you can't really take advantage of the machines' 100% habitability or the machine world ascension perk. And don't sass me about lore and RP — if I want my robots to have high morale on a mining world knowing that their trophies are happy and safe on some gaia world elsewhere, I don't see why I cant. Remember that the drones are not individuals, they're all extensions of one AI; it doesn't really make sense that only the drones near the bio-trophies are performing better.
And speaking of the unity "bonus" you get from bio-pops, is it even advantageous? They certainly start out making a lot more than other empires, but it seems like they might actually fall behind on unity production due to their inability to make upgraded unity buildings. Maybe there's an upgrade to the bio-pops or the sanctuaries in the tech tree, I don't know, I had to quit the playthrough because achieving a stable economy was proving completely impossible as soon as I tried colonizing, let alone keeping up with the other empires.