One disadvantage might be its sheer size (which is not strictly a downside of course). But if you want to go deeper in algebraic subjects, there is a point where you want to switch from "general abstract algebra" books like Lang's to more specialized stuff like more advanced group theory, commutative algebra, non-commutative algebra, representation theory, homological algebra, algebraic NT, algebraic geometry etc.
The point I'd make is that it's by no means necessary to read a ~900 pages book on "general abstract algebra" before you make that switch to more specialized stuff