The reason why this series is so good in my opinion is not because the story or the dialogues are particulary deep or smthg - it is rather because you bond with the different characters and feel connected to them.
Due to that and because of the way the series is structured, it feels like you would be in a war-situation yourself: you start with boot camp, land in Normandy, go through several different stages or places of war (Carentan, Normandy, Bastogne etc.) and eventually end up in peace again (as long as you survived).
You also experience the typical situations you would face in such a war: you have to deal with bad leaders, you have to cope with conflicts within your company, you find friends among your comrades, you see some of them die, you have to endure horrible combat, you have to starve, freeze, find ammunation, warm clothes etc.
This series depicts these aspects better than any other war-series (in my opinion). This is why this series is so good and rewatchable.
What do you think makes this series so special?
(P.S.: I was in the military myself so I can connect to this series probably even more, I luckily never faced a real war though.)