The disadvantage of the L&S version of CS is that you go in as undeclared (all L&S go in as undeclared). For CS, the first 3 required CS classes, you need to have a minimum 3.3 GPA in order to be eligible to declare for CS. Around 50% of students who try make it. I wouldn’t say that it’s that difficult to make the 3.3 mark, but not necessarily easy either. It does put a strain on students sometimes, as there is sometimes a lot of pressure to get a good grade in the classes and some students may not handle it that well.
For practical purposes for Computer Science majors at Berkeley or many other universities, there’s no difference between a BS or BA. It’s possible for some company to require a BS degree for CS jobs, but probably more out of habit more than anything. The FAANG companies for sure won’t care.
The only reason why an EECS major might be more prepared for say quantum mechanics than say a LSCS major would be that 1 year of Physics is required for EECS (required of all Engineering majors), whereas the classes are optional for LSCS. However, you can easily take the same exact classes as a LSCS student if you want.
EECS is actually the CS department, so all pages will be marked with EECS. Even though they are two separate majors, they share pretty much everything. Just as an FYI, Berkeley has other programs that have a split choice between two colleges as well - Physics (L&S and Engineering) and Chemistry (L&S and CoC) come to mind.