Paco Peña Company, Royal Festival Hall, London

Not many instrumentalists lead dance companies but Paco Peña, the celebrated flamenco guitarist, is one such. With the support of singers, dancers and two more guitarists he presents an ensemble performance in which the dancing is intimate and companionable, even in a venue the size of the Royal Festival Hall, and there's an emphasis on camaraderie over fierce individualism.

Not many instrumentalists lead dance companies but Paco Peña, the celebrated flamenco guitarist, is one such. With the support of singers, dancers and two more guitarists he presents an ensemble performance in which the dancing is intimate and companionable, even in a venue the size of the Royal Festival Hall, and there's an emphasis on camaraderie over fierce individualism.

That goes for Peña, too. He has several solos, but the heart of the evening is in the guitar duets and trios, where there's a mellow depth of sound under the sparkling detail. His singers have traditional flamenco voices, raw and wailing, but the tone is one of celebration rather than passionate gypsy grief. The greatest excitement comes from the percussion, with brilliant, clapped cross-rhythms.

Peña's young dancers can be surprisingly gentle. Angel Muñoz ends his first solo with a drum-roll of stamps that slows to a soft, quiet close. Alicia Marquez makes most impact through her hands and hips. Gestures are driven by her fluttering fingers and winding wrists, but she keeps her torso simple, bending very little.

Charo Espino is stormier, a matriarch in the making. She fixes the audience with a stern eye, whisking her skirts with an angry flounce, making the most of her powerful upper body.

Into this mix of traditional and modernist flamenco Peña's choreographer, Fernando Romero, injects a balletic influence. Like Muñoz, Peña's other male dancer, Romero doesn't put much emphasis on the torso. He pulls himself up more grandly for a balletic fourth position than for the raised arms and pointing fingers of flamenco.

Romero also has a balletic eye for floor patterns. In the first of his group dances, he sets the dancers on diagonals, and they move in straight lines, with the unison style of a corps de ballet. These are still flamenco steps, but they're diluted by the tidy organisation.

There's more freedom in the second group dance, and it's exhilarating. The dancers clump together, then drift off at will, The pace keeps changing. They raise their arms at once, but at different speeds, different positions and phrasing, each dancer responding individually to the music.

There's a return to traditional flamenco for the last numbers. The dancers step forward one by one, in concentrated bursts of dancing. The performance seems most personal here, with each dancer packing in favourite steps. The musicians lean forward for each new solo, relax back with a shout as it finishes.

In Naharin's Virus, the performers of Batsheva Dance Company stand about the stage in groups, breaking into solos or unison movement. Wherever I looked, there was a dancer stuck in an awkward transition. Perhaps they made it into their poses before or afterwards. If so, I always missed it.

Naharin's Virus is miserably full of things that don't come off. The political points are as woolly as the dancing. Batsheva is an Israeli company, now under the direction of choreographer Ohad Naharin. In interviews, he has supported Israeli-Palestinian reconciliation, and criticised the government of Ariel Sharon. On stage, his dancers scribble "PEASTELINA" on the wall and think that that counts as incisive comment.

Naharin's Virus is based on Peter Handke's 1966 absurdist play Offending the Audience. One of the dancers scrambles up the wall at the back and stands in a suit, reciting. Then he wriggles out of the suit - which in fact stands alone in front of him, like the sets of old-time seaside photographers - and joins the other dancers on stage. The wriggle is the show's one joke, and even that gets repeated to the point of boredom.

Meanwhile, the dancers stand about, write on the wall or scream. One girl provides childhood memories: dancing naked and being beaten by her mother. The dancers drift back to the wall, as the speechifier keeps climbing it to deliver more rant.

Then there are the outbreaks of dancing. The company lines up at the front of the stage, shaking their fists in unison or stepping out one by one in staggering solos. Barber's familiar Adagio is played in snatches, and the dancers move solemnly, but not well.

They're further hampered by Rekefet Levy's ugly costumes: black tights worn under white short-legged leotards, the arms ending in gloves - a cut which is uniformly unflattering.

Naharin's Virus begins and ends with Arabic folk music written by the Palestinian Habib Alla Jamal - another gesture of reconciliation. Here the steps are something like traditional folk dance - a simple, pretty folk step, but a very pallid performance. Naharin obviously cherishes his dancers more for their readiness to shriek and emote than for their dancing. Does he even notice when his dance steps trip them up?