General Synonyms:
* Amazing
* Fantastic
* Great
* Excellent
* Superb
* Splendid
* Terrific
* Marvelous
* Extraordinary
* Remarkable
More Specific Synonyms:
* For beauty: Breathtaking, exquisite, gorgeous, stunning
* For something joyful: Delightful, joyous, exhilarating
* For something impressive: Astounding, awe-inspiring, impressive, remarkable
* For something kind: Heartwarming, moving, touching
Formal Synonyms:
* For something highly praised: Exemplary, praiseworthy, commendable
* For something rare: Unique, exceptional, unparalleled
The best synonym for you will depend on the specific context and the feeling you want to evoke.