I upgraded from iPhone 6 to iPhone XS and if I am 100% honest I don't feel a massive difference. New screen is really nice and I am surprised that I actually like face id much more than the fingerprint scanner. But on a day-to-day activity scale ... browsing facebook, reddit, youtube, playing games, etc. ... I often struggle to notice any real difference, even in how quick apps start. I don't regret it because I know I won't have to worry about upgrades for another 2-3 years.

But I can highly recommend the battery replacement for the iPhone 6. I was luck (unlucky?) enough to get the discounted battery replacement due to mine failing. After I got that it was a significant improvement.