S4 really is a great work, despite its length and structural weaknesses. Chung/Philadelphia on DG, which I recently acquired, is quite good as an "objective" approach. Previn/CSO, which didn't impress me on previous hearings, is outstanding.
Whenever I hear S12, I have the same reaction: I don't need to hear this again for a long time. It seems many listeners put S11 in the same category, but in recent years its star seems to have risen, including with me. I like Bychkov/BPO, one of few BPO recordings where the tamtam sounds really respectable.
Speaking of Previn/CSO, his S4 and S5 were recorded at Medinah Temple; many CSO recordings were made there because the record companies found Orchestra Hall unsatisfactory after the 1967 remodel. The CSO recorded there over the course of three decades, until the mid-'90s. As it happens, I just finished a contract job that had me walking by the building frequently on my way to work. It is incredibly beautiful. It had fallen into disrepair, but was extensively remodeled and served as the site of a Bloomingdale's Home store until last year. Now, it is a "flagship retail opportunity."