Formal:
* Articulate: Able to express oneself clearly and effectively.
* Fluent: Speaking or writing smoothly and easily.
* Persuasive: Able to convince or influence others.
* Sonorous: Having a full, rich, and pleasing sound.
* Moving: Evoking strong emotions.
* Poignant: Evoking a keen sense of sadness or regret.
* Lyrical: Having a musical quality.
Informal:
* Sharp: Quick-witted and intelligent.
* Witty: Cleverly amusing.
* Charming: Pleasing and attractive in manner or appearance.
* Compelling: Very interesting and engaging.
* Captivating: Holding someone's attention completely.
Other options:
* Effective: Achieving the desired result.
* Impressive: Making a strong and favorable impression.
* Impressive: Making a strong and favorable impression.
* Memorable: Easily remembered.
The best choice will depend on the specific context and the desired tone.