Because of Sion's K/D/A and utility, he has a fairly average overall win rate. He does very well in the early game, with a winrate of 51.6% in that phase. Unfortunately, he does poorest in the mid game, where Sion's winrate is 49.5%., The difference between his best and worst game phases is only 2.1%. This small difference indicates that his relative power is uniform throughout an entire round.
Sion has been used a lot in the latest ranked League of Legends games. In the current meta, his popularity is 7.5%. Hardly anyone sees him as a threat. He has only been banned in roughly 4% of League matches.
Sion is played mostly in the top position. This happens in 79,6% of his rounds. Yet, top Sion has the highest win rate (52,3%) of all positions but is less popular of a position (played 9,8% of the time). Currently, Sion's meta game is centered around tanking. Specifically, his gameplay should primarily be centered around shielding carries. Additionally, he is an ok physical damage dealer champion. Dealing magical damage is the least significant part of Sion’s kit.
You should expect to have to to spend a decent amount of time practicing and learning to get good at playing Sion. Most LoL gamers consider he is an average difficulty champ to get good at. Sion mostly causes physical damage (64% of his total damage). He also deals a significant amount of magic damage.
Sion deals a great deal of damage over the course of a normal round (21.892 damage). You should focus on building him as a damage dealing champ to destroy your opponents.
He is an average damage dealer in the game with 4.4 kills on average per match. That is one of the lowest kill counts amongst all tops. Additionally, he has a fairly high average champion death rate (6.7 deaths). Moreover, Sion has a low KDA ratio (1.5) with 5.5 assists.