TLDR: I personally dislike alignment as Personality Type (e.g., MBTI, astrological sign, etc.) for PCs and monsters; however, I enjoy alignment as Moorcock-style Cosmic Factions, especially when it is done well.
I dislike having Good/Evil as a separate axis from Law/Chaos, because (IME) the former conflict tends to greatly trivialize the latter.
I like 4e's alignment setup (i.e., LG, G, UA, E, LE) as that resonates more with (1) the World Axis setting's Chaoskampf themes, and likewise (2) it fits fairly well IMHO with the worldview and mythos of ancient Mediterranean cultures (again, the Chaoskampf motif) and how wickedness leads to cosmic disorder, chaos, and the unmaking of the created order, which is regarded as "good."
I also like Law vs. Chaos alongside Balance/Neutral/Unaligned. It makes for a more interesting conflict, especially in the absence of good vs. evil to fall back on.