It's a shame that Upstairs Downstairs has been eclipsed by Downton Abbey - I would urge any Downton-lovers who didn't return for the latest instalment of Upstairs to give it a go on DVD: you are missing something rather marvellous. Series one of Downton was magnificent; but series two was under-powered and sometimes threatened to be a camp travesty of itself. Upstairs, on the other hand, has continued to improve and develop in wonderful and surprising ways as the series progressed.
The worlds of almost every character in Upstairs are beautifully drawn and complex, unlike those in Downton that too often are of the single note variety (Maggie Smith is arch - there is nothing left for her to do than raise an ironic eyebrow). In particular, Lady Persie (Claire Foy) and Mr Pritchard (Adrian Scarborough) are endlessly fascinating and never as straightforward as they appear on the surface. You meet a character such as archaeologist Dr Motteshead (Alex Kingston) and at first she seems every bit the stereotype of the intellectual 1930s lesbian; but then, as the series evolves, expectations are confounded through great writing and an excellent performance.
Upstairs handles its period detail and sense of time perfectly with none (well I didn't spot them) of the anachronisms that irked me so much in Downton. Moreover, it is really engaged with the history taking place as the drama unfolds - I can think of no other drama that has dealt so well with the mindset of Britain on the eve of war. Scenes such as the household watching the streetlights of London being turned off for the final time are deeply moving. Again, I can also think of no other TV costume drama that has been more beautifully designed, lit and shot. This is far more noticeable in series 2.
For me there were 2 downers to Upstairs: the sometimes maddeningly short scenes and the miscasting of Ed Stoppard - a charisma-free zone. But these are minor niggles for a series that has proved so engaging and full of so many rewards.