This is not a compelling upgrade from the S22 Ultra, however, very few people out there are going to do a one model year upgrade on a ultra expensive smartphone anyway.
This phone is extremely similar to the S22 Ultra with the only major exception is the new camera sensor. This harkens back to the old Digital Camera Megapixel Marketing War days where the marketers know that you average Joe thinks "more is better." What ending up happening was quite the contrary... more pixels = more noise. But most consumers are pixel peepers and sensors and processing technology have evolved.
Still, the first comparisons I've seen of actual photos taken with the S22 and S23 Ultra point out there is no major leep in image quality. A small incremental improvement, IN CERTAIN CASES, and otherwise a very subjective improvement (or small step back) in others. The lenses are the same so this shouldn't be a total surprise but for those always jonesing to have the "latest greatest" they may need to exaggerate the improvements of this phone compared to the S22 to justify a purchase without having buyer's remorse.
Here's the CNET article where you can compare photos:
The camera on Samsung's new high-end phone already shows promise.
As you can see, the conclusions are mostly subjective opinions. My own opinions is that the main area that is most beneficial when improved is low-light performance. On the S23 compared to the S22, the low light performance looks to me to be about equal just depends on which color tint you prefer. Maybe one could argue the S23 is objectively better but if so, it's not a big enough difference to justify the higher cost. If the "improvements" were more night & day (no pun intended) I might have a different opinion.
I've got a Note 20 Ultra and am ripe for an upgrade. Gen 2 instead of Gen 1 and slightly flatter Victus 2 instead of Victus+ glass are also not changes that warrant the extra cost of an S23 over an S22 refurb in my opinion as these minor spec improvements are thrown out as bait for that person that's use to spending $90 a month on their service+discounted phone payment (as they never could afford to fork out $1K upfront.) The best deal on this phone right now is Amazon for $1,199 less $100 for a $100 gift card = $1,099. Samsung Store app with a Samsung Membership will be $1,199 for a factory unlocked model but they throw in a watch5 which you could hawk on Ebay for $150 but that's kind of a hassle. (I personally get unlimited on a Verizon MVNO with excellent service for $35 a month and always only buy factory unlocked, unbranded phones, last years model at a discount. I've probably saved at least $20K over the years compared to being lured into these latest free phone deals tying you to expensive monthly plans.
You can get a mint refurb S22 Ultra for as low as $700 on Ebay and eventually Amazon in another couple months I imagine. Is a new S23 Ultra worth $500 more? Not.
Keep your Note 20 as long as you can. I've had the s22 ultra and most Notes and I'm 100% sure the Note 20 is a better phone no matter what the specs say. Not sure what it is, possibly the chip, but since new the ultra will sometimes just freeze up like a pc with low memory- the Note doesn't. The s23 is essentially the same as the s22, the new one has a larger rear camera but the old one has a larger front one. New is smaller in size but appears slower on the performance tests.