I don't see much use out of either other than as a line on a resume. With that in mind, I'd choose IEEE - more well known than ACM. (And if you're getting the t

I don't see much use out of either other than as a line on a resume. With that in mind, I'd choose IEEE - more well known than ACM. (And if you're getting the type of membership providing access to research libraries, IEEE will cover a far broader range of topics than ACM).