In the looks department I see them both being very very similar if you were to match the components on each of the bike. Although a big distinction to me that the 2023 has the metal mud guard from the factory which looks very elegant compared to anything aftermarket that you could get for the 2024 model. Although the majority of people I see with any Svartpilen in general removes the metal mud guard in favor of the tail tidy.
The weight difference between the two are very similar. The 2023 as a wet weight of 335 compared to the 2024 which is 15 lb heavier although if you remove the metal mug guard on the 2023 then you save an extra 8 pounds less totaling 23lbs. However the 2024 has an extra 1.5gallon in the tank which matters more if you do any long distance driving.
I think a big factor to consider is the screen on the 2024 which is color and quite easy to see in the sun compared to the 2023 which is black and white and hard to see in the sun. The 2023 screen suits the bike more since the headlight and the mirrors are round which they should have done the same with the 2024 because the square screen kind of throws off the theme.
The display on the 2024 is an upgrade for sure.
When it comes to looks I think they are pretty different. The 2024 has a cheaper looking headlight and the rear lacks the short slimmed looks of the 2023. I also like the frame on the 2023 a lot better and I don’t like the under swung exhaust of the 2024. Both are great bikes.