It all depends on which games you prefer. Sure, the Scorpio will probably outpower the Pro, but if you prefer PS's exclusives over MS's, then why bother with their console unless you have a bunch of money and can afford both or if you just REALLY must have a 4K bluray player?
Here's the problem with that argument: This generation of consoles has no exclusives good enough to justify a single console purchase.
Alright, so then what games are on this generation as exclusives that are worth it? From the PS4 side all i can see is horizon zero dawn, the last guardian and uncharted 4. The rest are meh or on the PS3. As for the xbone, we've got... forza and halo 5. You know, this generation of consoles really is shit.
PS4 will have the new Crash Bandicoot and FF7 remake as exclusives I think. Last of Us 2 will be I'm sure. Persona 5?....although this may be on PS3 too? And then Gran Turismo Sport if I want to bark down your alley...which I dont.
Oh, I won't argue that the Xbones exclusives are lacking. They may have a couple, but Halo and Gears never interested me after playing through the first couple and racing games get boring quickly. For PS4 though, other than what you've mentioned, there's Bloodborne, Infamous Second Son (which I enjoyed), Yakuza 0, Gravity Rush 2 (which I haven't played, but adored the first one on Vita), and Nioh. Then there are upcoming games such as FF VII Remake, God of War, Death Stranding, and Last of Us 2. I see all of these game as "worth it," even if you don't.
I wont say that the Scorpio is a better buy, but I respect if you think it is. It's all about games to me. Sounds like Scorpio is clearly the more powerful system, but I've been sitting on my X box one with like no games to play for a long time. They just don't have the exclusive that call to me. PS4 does, so if I'm upgrading, it will be that. I have PC to do the rest.
In terms of a library, there's not much of a difference between the X-Box One and PS4 systems. As for exclusives, I do prefer the PS4's, with games like Uncharted 4: A Thief's End and Horizon Zero Dawn. I honestly can't think of many other exclusives, but to tell you the truth I still enjoy the PS4 regardless.
PlayStation has the strongest, and most, exclusives right now. However, owning both consoles has solved this issue for me.