The most sorted out perhaps but also the most cheapened, and with the most troubled and expensive to rebuild transmission. For 1990s for Mercedes was a mad dash to reduce build costs while trying to minimize degradation of the product. Sometimes they won, sometimes they lost. A mid-90s S320 with HFM and 722.5 transmission is a very nice car, same EPA rating as the later cars, better in many ways for a DIYer, and very much worth considering. Wiring harness issue, yes, but they have virtually all already been updated.