I don't want to compain too much. The first two are very good on their own merits: Nigel Fairs' Jago in Love takes the duo to Brighton, where Jago, as one might guess, falls in love and Litefoot is haunted by a lovelorn ghost. Trevor Baxter in particular does a brilliant turn as the possessed Litefoot; Christopher Benjamin as the besotted Jago is not surprising but still entertaining.
John Dorney's Beautiful Things sees Alan Cox totally stealing the show as Oscar Wilde, playing him as a sharp-tongued, quick-witted, mildly Irish man of action, who out-alliterates Jago, makes a dreadful pun on the name of fellow-Irishman George Bernard Shaw, and saves the day. Louise Jameson also gets some great lines as Leela, hating the new Wilde play (A Woman Of No Importance). The plot is a clever riff on Dorian Gray, though I did not really feel the villain's means were adequately explained.
Matthew Sweet's The Lonely Clock felt a bit less integrated. Sweet is excellent at weaving literary allusions into his Who scripts, but I didn't spot any here (apart from Leela doing a Sherlock Holmes impression). There are lots of fantastic images - a glass business card, a time-travelling tube train, people frozen in time - and an excellent guest performance by Victoria Alcock (one of the passengers in Planet of the Dead) but it didn't quite come together for me.
Justin Richards is a hit-or-miss writer, and I'm afraid The Hourglass Killers was a miss for me; Colin Baker's character has adopted the pseudonym Claudius Dark for no good reason, Kempston and Hardwick imprison Terry Molloy's character Lord Ampthill in an hourglass for no good reason, there is a very silly scene in the British Library, and the denouement is reminiscent of the Silvester Stallone film Daylight except rather less plausible. The ensemble cast are all having good fun, but we are dangerously close to jumping the shark here.
I am still looking forward to the next season, even though it will have no Leela; I think the writers may find it easier to write good stories with only two main characters to write about. One of the problems with this season, I felt, was a bit of a tendency to put stuff in just so that the characters had something to do.
I greatly enjoyed The Davros Mission, by Nicholas Briggs, set between Resurrection of the Daleks and Remembrance of the Daleks, in which a Thal agent played by Miranda Raison infiltrates the ship on which Davros is being transported as a prisoner to Skaro by the Daleks; there are some excellent two-hander scenes between Raison and Terry Molloy, and the darkness of the main plot is balanced by two mildly comic aliens who are Dalek slaves. Big Finish's Davros spinoffs in general are amog its best work.
In summary, The Davros Mission is well worth seeking out, especially as it comes as part of a job lot with the other Davros plays; and the first half of Jago and Litefoot's fourth season is mostly good, while the second half is mostly OK.