The obvious difference would be the cup competitions - Spain, Germany, Italy and Holland only have one cup competition per season, and in the case of the Coppa Italia, DFB-Pokal and KNVB Cup all matches are decided on the night with no replays, while the Copa de Rey is a two-legged affair. Compare this to the Premier League, where there's both the FA Cup and the League Cup, and in the case of the FA Cup if a tie isn't decided the tie is replayed.
However, that doesn't explain one thing: Ligue 1 kicks off at the same time as the Premier League, they have two cup competitions (the Coup de France and Coup de la Ligue - although neither has replays) yet they have a winter break.
That means European clubs won't be able to sign players from South American clubs until the January window (and vice versa) which is a directly violates laws laws on freedom of movement for workers.