That depends on context. Do you have any?
When 'A and B alike' is a subject, do we regard it as a unit or two separate units?
Thanks a lot!
As a subject, I would generally use a plural verb.
As far as I can work out, you can only use "alike" with two or more items, so it has to be plural. "Alike" doesn't unify the items.
Then I say, "A and B alike are both good choices."
The use of both is proper, right?
I am not a teacher.
"A and B alike are both good choices." sounds like overkill to me.
"Both" is good, it's "alike" that doesn't work.
I think you mean, "A and B are both good choices." or, " "A and B are equally good choices."
To use "alike" adverbially you would have to turn the sentence around to something clumsy like, "The [quality of being a good choice] applied to A and B alike."