Apart from a moral stand-point, I don't believe that one is better than the other. It depends on the type of Nation you want to form and play as. With that being said, you still get a lot of manpower when expanding the definition ;)

you missed the opportunity to make a pun using the ethic-ethnic rhyming Wernher

Damn it, even when you point it out, I don't see it

well 1 gets some good nation thingys one of which some more manpower, research production advantages, other gives plasma weapons reduces influence of legitimacy, and could get you f.35 modern jet. some event require one or the other. So what Wernher said, look at the effects of the trees and see what fits your playthrough the best. I went full democratic and embraced the new world, all of the new world as the new america states.

I also did that once and all the manpower you get from the power grids is ♥♥♥♥♥♥♥ crazy

I looked at the segregation tree and its not that good, f35 are not that helpful considering no one really builds up their airforce and even if they did most nations are not advanced so you could still get better fighters, as for plasma weapons, you get them anyway after you annex area 51

and the manpower penalties are pretty brutal
you get a fourth of your recruitable population slashed while making it harder to build power grids

What you get from Area 51 is random according to my experience. Once I got an F35, another time I got Plasma. Don't if it's just those too or also other Tech. While you are right that most nations don't have an airforce, what my experience showed though is that many major nations like BoS, NCR, N. Broth. and sometimes even the Legion have pretty big airforces.

really? ive never seen the leigon or BOS build an airforce

I am not a 100% sure though. Should probably check that later. That was also on an earlier version of OWB.

I've discovered that I rarely struggled for manpower as the reformers, regardless of the route I chose to go down. But I also practice they playstyle of spamming PA divisions only.

With the new update to OWB, I do believe that the manpower increase will be more relevant though as you will need to field more non-PA units.

I like going down the Segragation path because its more interesting but I can't help but feel that at that point I'm just doing a watered-down Purist run.

The other big question is whether you reform the United States or the Enclave.