Whether StarCraft II is "good" depends on your preferences, but it is widely acclaimed as a landmark real-time strategy (RTS) title.
If you love complex strategy, sci-fi settings, and competitive depth, StarCraft II is essential. If you prefer low-stress, narrative-driven, or purely casual play, it may feel overwhelming. The base game is free-to-play, so trying the campaign and co-op is risk-free.