Indeed I had the same few years ago and made the same move: let a PP go for getting a Datograph also Platinum version (the rose gold one is beautiful too but for me the only "real" Dato is the Pt version).
I confirm to you the Datograph is gorgeous to look at: masculine, elegant, unique look, modern and sophisticated but... an important thing to know about is that it is not the most comfortable watch on earth due to its relatively heavy weight (a massive block of Platinum, thus a feeling of solidity but also sometimes some discomfort on the wrist), and also it is very high on the wrist (a thickness of 12.8mm simply not adapted to my chickens wrists).
In short the Datograph is a true beauty, certainly one of the finest chronographs but it was not adapted to my morphology.
Probably the 1815 chrono in WG version would have fit better on my wrist but instead of making this choice I came back to PP and traded my Datograph for a chrono perpetual calendar (3970) which was more adapted to me (I should rather say to which attractivity I could not resist in spite of the money I had to add on top obviously).
As for my opinion on the 5396R I can understand your fear of scratches on the flat bezel as it is certainly the weak point of this watch: I can hardly imagine it can stay in mint condition if you wear the watch regularly even if you are very cautious. This is the advantage of a smooth rounded bezel like on the 5125 (also annual calendar).
I will not comment on the sector dial as this is a pure question of taste: it has its detractors and its fans.
All that being said, the real question behind is not only between 5396 vs Dato but more between PP and L&S (just like the often seen question for choosing between a Calatrava and a Saxonia).
And there is no real answer to this question: they are both the finest watchmakers, both of them the epitom of their national watch industry one being swiss the other being saxon=it's a question of philosophy, brand image, positioning in YOUR mind.
Finally and this is surely not the most important as we talk between watch addicts out of any speculative perspective, it is to be noted that if you talk about a sought after model for both brands, a PP watch will be probably easier to resell than a L&S if the strange idea comes to your mind that you don't want to keep the watch for whatever reason.
My 2 cents...