Hi, I'm pretty sure the material in the two versions is identical. I only had the 1980s algebraic one, but it reprints Keres's preface from 1974 which suggests an unaltered reissue, and Keres died in 1975, so he can't have done any updating himself. It's therefore purely down to which notation you like (unless you're into condition/collectability considerations).
The book does have a well deserved reputation as one of THE chess books to own and study.
Thoroughly agree with the comments on the 1989 algebraic edition of Levenfish and Smyslov, I've never known anything like it for the sheer number of misprints.