Nothing galvanises an audience quite like physical risk. As soprano Sarah Tynan rose on a hoop into the darkness, intoning the final words of "Départ" from Britten's song cycle Les Illuminations, you could almost hear her heart race. Beneath, a troupe of circus performers held the rope – and her life – in their hands.

In choreographer/director Struan Leslie’s vision, performers decked out as Rimbaud’s "sturdy rogues" brought sinew, grace and heart-stopping spectacle to a night illuminated by explosive, raw-fresh string music: it was all about the vertical.

"Bad Star Trek episodes" is how one director describes a certain unfortunate look in would-be intergalactic opera productions. The late Nikolaus Lehnhoff came perilously close to it in his Glyndebourne Tristan und Isolde but offered a coherent vision. Daniel Kramer, now ENO's Artistic Director, has a few "bad Star Trek episodes" and many good ideas that don't always join up or else outstay their welcome. Unevennness abounds: hideous costumes and makeup clash with Anish Kapoor's eventually brilliant designs, singing and conducting are only patchily inspired.

Wagner was never satisfied with Tannhäuser, and it’s not hard to see why. Essentially a study of the tension between sensual and spiritual love, it was composed at a time when, by his own later confession, he lacked the resources to deal properly (that is, improperly) with the sensual element, and even in any profundity – one might feel – with the spiritual. The piece went through numerous revisions, extensions, compressions, tinkerings of one sort or another.

Opera North’s ongoing Ring isn’t taking up much of the chorus’s time, which presumably is one of the reasons that many of its members have decamped half a mile east to collaborate with the West Yorkshire Playhouse in an eye-popping new staging of Sondheim’s Into The Woods. That opera companies can and should stage Sondheim is vindicated by this production: the musical values are superb, my only niggle being that James Holmes’s excellent pit players are hidden offstage. The tricksy ensemble numbers are dazzling, with every word and melodic line thrillingly clear.

"Better than Puccini," raved one Tweeter after the final rehearsal of Opera Holland Park's season-opener. Nonsense: "nearly as good as Puccini" is the best any of his Italian contemporaries could hope for; that applies to Leoncavallo and the Cilea of Adriana Lecouvreur. Mascagni is more arthritic in his sense of movement – think of how long the plot of Cavalleria Rusticana takes to get going – and sometimes strives hard for those orchestral effects which seem so natural in Puccini.

The Orchestra of the Age of Enlightenment is 30 years old, and last night it celebrated in style. The orchestra has a long association with the music of Weber, who became iconic of their pioneering work in presenting 19th-century repertoire on period instruments. His greatest work received an impressive performance last night, one that demonstrated the many virtues of their unique approach to the work of the Romantics. But it wasn’t all a success, and was let down by a surprisingly modest staging concept from the usually ambitious David Pountney.

Though composed after and based on a play by the same author, Puccini’s spaghetti western is in no way a sequel to Madama Butterfly, his whisky-sour eastern. Fanciulla is Butterfly’s opposite in almost every respect, and to tell the truth it isn’t much at home in a small theatre like the one at Grange Park. Where Butterfly is delicate and light-handed, its successor is loud and punch-drunk. Its heroine is no frail Puccini victim but a tough mother figure surprised by true love.

Common wisdom has it that the prolific output of 20th century Czech genius Bohuslav Martinů is very uneven, a judgment surely made without a complete hearing. Some listeners shrink from his fidgety polystylism. Many of us on the fringes of the Martinů hardcore, though, have found ourselves giddy with each new discovery of music we didn't know before: last year, string duos on a CD from viola-player Maxim Rysanov, this year piano trios from the Czech label Supraphon and now two one-act operas, this time live from Guildhall students.

Seventy years ago, almost to the month, Welsh National Opera took to the stage for the first time with a double bill of the terrible twins, Cavalleria rusticana and Pagliacci; and fifty years later the company celebrated with the same two works directed by Elijah Moshinsky, designed by Michael Yeargan. To repeat the exercise in the same productions after another twenty years might seem an egregious piece of navel-gazing. But Moshinsky made a clever point with his 1996 staging, about stylistic distances travelled and technical standards raised.

New operas are a risky business, or so the Royal Opera’s past experience teaches us. For years, visiting the company’s Linbury Studio Theatre was like rolling the dice while on a losing streak: vain, desperate hope followed inevitably by disappointment. Glare, The Virtues of Things, Clemency, the failed experiment that was OperaShots. But recently things have taken a turn. Gradually, thanks to works from Birtwistle, Haas and more, the risk has begun to pay off.