top-notch vs A-one

top-notch and A-one both are adjectives.

Word	Noun	Adjective	Verb	Adverb
top-notch	No	Yes	No	No
A-one	No	Yes	No	No

As adjectives, top-notch and A-one are synonyms defined as:

Other synonyms of top-notch include ace, crack, first-rate, super, tiptop, topnotch, tops.

top-notch (adjective)	A-one (adjective)
of the highest quality	of the highest quality