Mamma Mia! Here we go again. “Nothing short of a triumph on all fronts,” raved the Chicago Tribune after Das Rheingold, night one of four. Like every Hamlet and every Tempest, however, every “Ring” gets some things all right and some things all wrong. Attendees’ satisfaction will therefore depend on preferences, priorities, tolerances. Definitive interpretations of the three roles at the very top of the totem pole may be too much to expect, but, hey, you never know. In other iconic roles, there are many talents to be grateful for, and Sir Andrew Davis on the podium is unlikely to disappoint. After three installments, the trustworthy Chicago Classical Review called David Pountney’s production “wildly uneven” (Götterdämmerung, the grand finale, is new this season)—a judgment borne out by the visuals we’ve seen so far. But honestly, the best of them look worth the price of admission. —M.G.