It's pretty good. Not as intrinsically good as the similar Midsummer Night's Dream and Comedy of Errors, but close: the main plot of the siblings being confused with each other is neatly done (though interestingly with a much stronger role for the sister than the brother); the subplot of Malvolio's fall needs more careful treatment, as it is basically the humour of cruelty, and one needs to make Malvolio monstrous enough not to engage too much of the audience's sympathy.
Arkangel have done one of their best productions here. Niamh Cusack is Viola; Julian Glover, doing a Scottish accent, is Malvolio; Dinsdale Landen is a suitably disgusting Sir Tony Belch; Arkangel stalwart Amanda Root is Olivia; and most gloriously, Paterson Joseph is Feste, playing it as if it was the role he was born to play (as of course he does with everything) - particularly when he is playing Feste playing the clergyman Sir Topas. Somehow the chemistry seems to have worked between the big name stars, and the result is fantastic.
Henry VI, Part I | Henry VI, Part II | Henry VI, Part III | Richard III | Comedy of Errors | Titus Andronicus | Taming of the Shrew | Two Gentlemen of Verona | Love's Labour's Lost | Romeo and Juliet | Richard II | A Midsummer Night's Dream | King John | The Merchant of Venice | Henry IV, Part I | Henry IV, Part II | Henry V | Julius Caesar | Much Ado About Nothing | As You Like It | Merry Wives of Windsor | Hamlet | Twelfth Night | Troilus and Cressida | All's Well That Ends Well | Measure for Measure | Othello | King Lear | Macbeth | Antony and Cleopatra | Coriolanus | Timon of Athens | Pericles | Cymbeline | The Winter's Tale | The Tempest | Henry VIII | The Two Noble Kinsmen | Edward III | Sir Thomas More (fragment)