What's interesting, the 9sp Shadow design Altus (RD-M2000) costs more than the respective Acera (RD-M3000) on most sites. And from the looks of it, the new Alivio RD-M3100, besides small differences in the outer paralelogram plate design seems to be the exact same as Altus RD-M2000. Perhaps Shimano have decided there's no point to three different entry level product groups, and are looking to merge all three A-groups between Tourney and Deore into one?