A comic book can be both a story and a volume. Sometimes a single comic book tells a complete story, while other times it's part of a larger volume that contains multiple related stories.
It depends on your taste. If you like superhero comics with complex characters and exciting plots, then you'll likely think it's good. The world-building and character development are quite impressive.
The Invincible comic has indeed come to an end. The story reached its conclusion after a successful run. Fans have had to say goodbye to this beloved series.