Almost a week in and my S10+ remains unremarkable and below par IMO for the battery size. Yesterday for example I went out for the evening straight from work and it was 100% at 5:15pm when I left work, I had 30-45 minutes on a train listening to spotify and generally looking at the phone on and off. It went onto flight mode for 90 minutes (I was at a football match) and when I got home just after 11pm it was just above 50%. Personally I think that is disappointing.
For comparison with phones I have owned over the last year or so I would say it is worse than the Note 9, Xs max S9+, Mate 20 pro, Mate 10 pro, View 20, Pixel 2 XL, it is also IMO slightly better than the following overall but worse for standby LG G7, V30, 3XL, iPhone X. Yes I am a phone addict!
Curiously yesterday I received a background power use warning for an app I had previously restricted in the background so maybe there are some software gremlins for Samsung to iron out, I also mentioned on a previous post that you cannot restrict facebook services (you could on the Note/SA9+) so maybe that is chewing from some power? maybe also there is a difference between SD and Exynos. Overall though I'd describe my battery as not terrible but below par.