Science does not yet know if Earth is extremely unique or just another planet in the Green Zone, a condition of habitability for a planet based on mostly whether liquid water could be found there, but taking other factors into consideration.
Even when a planet is habitable, life had to start there (or be transplanted there). And its a long set of circumstances that leads from primordial soup to oceans and forests and the like. You need the spark of life to develop according to the available conditions.
Earth benefits from its large moon and medium star and its axis and time of rotation and all kinds of other factors.
Time will tell, but most likely not in our lifetimes, if life is so resilient as to succeed in completely different environments or if there are other planets similar enough where the spark took off. With so many stars in just our galaxy and so many galaxies, I'm betting on a bit of both (resilience of life and other earth-like plsnets) making us not so unique.