The players seem to like Charlie, and there have never been any clubhouse issues or disgruntled players. He puts a lot of trust into his players, even at the detriment of team success some times (ex. starting his 3rd string catcher in an important September game against the Rays when his two main catchers were both on hot streaks, keeping a clearly struggling Ryu in the game for one more batter with a predictable ending, etc). The players probably appreciate things like that even though fans hate it. Really, that's probably his only strength. He is a player's manager.
Beyond that, his in game decision making is awful. Horrendous, actually.