Individual discussions of each below the cut, but one common slightly disappointing factor is that John Barrowman seems to be under sedation for all three plays. I guess he is just one of those actors for whom the visuals are essential - certainly, having seen him on stage, he seems to love the thrill of interaction with his fellow-performers, which perhaps is rather different in a sound booth (and I'll note again that I wasn't impressed with his reading of The Ancestor Cell). In the first and third plays it doesn't matter so much since Jack is less prominent, but it rather takes the shine off The Golden Age. (I will add that the female guest stars in all three plays were excellent.)
Anita Sullivan's Asylum centres around Gwen, Andy the policeman, and Frieda, a girl from the future who has mysteriously been thrown into today's Cardiff. I found the ending inconclusive but none the less intriguing. Erin Richards is great as Frieda, and there is a nice Jack/Ianto exchange as they play with the weapon she has brought with her. I thought Andy's character was pushed to places where a beat policeman wouldn't normally go, but Tom Price carried it off well.
(Big space to allow for those who haven't heard the other two plays yet.)
James Goss's The Golden Age is just a bit silly: back in 1924, Torchwood's Indian branch retreated inside the timeproof walls of a gentlemen's club in Delhi, using salvaged alien technology which now needs to be fed, Matrix-like, with human lives. Oh yes, and it is run by a Duchess who is an old flame of Jack's. Obviously this has to Be Stopped, and our team does it, though as mentioned above with an audible lack of enthusiasm from the show's star. Jasmine Hyde is, however, suitably dotty and homicidal as the Duchess. (Though she ought to be addressed as "Your Grace".) Eve Myles and Gareth David Lloyd are not given much to do other than wander round and get captured, but they do it very well.
(Space left for those who have't heard The Dead Line yet.)
Phil Ford's The Dead Line is probably the best of the three. Here we have the focus on Gwen and Rhys, for a change: all over Cardiff people are collapsing into comas when answering the phone. Jack becomes one of the victims, and Ianto can't tear himself from Jack's bedside (which gets Gareth David Lloyd a nice soliloquy about the future of their relationship). We meet another of Jack's old flames, a neurologist played by Doña Croll (probably the best known of the guest stars), which gives an excuse for much gossip about the 1970s. Eventually Gwen and Rhys track down the problem to a building society's internal phone system; it is all suitably horrific, though I found the ending a bit abrupt and had to play it again to make sure I wasn't missing anything.
So, three worthy additions to the Torchwood canon. There is no internal order to the plays, so if you can only listen to one make it The Dead Line.