This is difficult given that both of their reactions to their respective tragedies were entirely unrealistic. With the way Sasuke's personality was, you'd have thought Itachi killed his dog and not his family and with Naruto you'd think he was just a regular delinquent. I can't take it too seriously.
Naruto- I'd have no one to raise me properly but eventually find someone despite being hated (Iruka) and gradually make friends from there while gaining a good rep in my beloved village. It would be lonely and I'd be obsessed with ramen (that junk food). I would never fully know a parent's love until much later, but would know some of it via my interactions with Iruka and Jiraiya.
Sasuke- I would lose a family I wasn't even too close to (he was just close to Itachi, his parents didn't pay much attention to him) and only thought of when I wanted acknowledgement as I was in the shadow of my brother. Then, I'd see a nightmare twice in my life but only be able to recall about a minute or less of it. And, I would get a full night's sleep every night given the day after the massacre, I just woke up in the hospital and asked myself if it was a dream... so not even the incident of that night was enough to leave an impression, it took me some time to get used to it. And the person who killed my family was a brother I adored because he was a measuring stick for me but I'd already partially hate him out of envy. I'd have a purpose to live instead of committing suicide due to my bro's plan and not lash out at people who don't deserve it unless they come at me first. And then, I'd find out my brother was innocent and the clan/village were in the wrong, throw a fit, then move on in life.
^That sums it up for what happened to them without all the melodrama bs.
If I were in Naruto's shoes and hated by an entire village, I wouldn't be so inspiring and if I were in Sasuke's, I'd have not wasted my time and progressed quicker (not just training with the same kunai tricks in the academy, but try to learn new ninjutsu every month)- getting vengeance after my brother sooner and upon learning the truth I'd change the shinobi system diplomatically. But, I'm a different person than both because I don't seek acknowledgement actively so life wouldn't slow me down so much and I'd be fixated on my direct goal.
I am also more ethos and logos oriented than pathos, so I would not make the same mistakes Sasuke did (ex: Never experience Tsukuyomi as I would not attack Itachi twice when I know he's stronger than me lol... I'd wait until I was confident I could give him a fight, not go to Orochimaru and instead teach myself jutsu in the village the same way ninjas before me did (Tobirama, Hashirama, Itachi, and many more), never have to attack my comrades as I would keep my village affiliation and I'd go on a short vengeance trip (as I would go after Itachi only when I'd know I was ready) like Shikamaru was approved to do with Hidan, etc. Honestly, Sasuke's life could have been drastically better quite easily, but Kishimoto just wanted to use him for the sake of creating conflict in the plot line.
I guess I'd take Sasuke's as there would be some direction whereas if I were Naruto, I'd have nothing.
No matter what, I wouldn't want to have Kabuto's, Yamato's (Orochimaru's test tube baby, yikes!), or Itachi's childhood pasts for obvious reasons though.
But if you meant which life would I have in real life and not within the context of the shinobi world, well neither is possible as in real life entire villages/cities/etc don't hate small children for something another did and parents/families are not idiotic enough to add fuel to the flames and commit suicide via a failed coup attempt after rejecting negotiation options and when they are not oppressed economically or really location wise (the Uchiha had better living conditions than most in Konoha despite being in the outskirts) and just have their pride hurt. Tailed fox spirits who destroy villages and teenage double agents with the capacity to kill a large group of people (without explosives or poison) don't exist either. So, other than the loneliness aspect Sasuke/Naruto are not possible to relate to with their pasts.
I find killing one's own parent to be the greatest sin in real life though, so Kabuto's and Itachi's stories are really hell imo. Words would never do justice to what those characters felt.
