The Sweeney is simply the greatest television programme ever made, and this is one of those box sets where they seem to have gone out of their way to cram extra goodies in. That adds up to a brilliant package.
Besides the material mentioned elsewhere (all the episodes, the pilot and both feature films) there are whole episodes from other shows, including 'Special Branch' (with Dennis Waterman in the guest role that apparently got him the job as George Carter), and "Thick as Thieves", the sitcom John Thaw starred in (opposite Bob Hoskins) before the Sweeney. There are even PDFs of The Sweeney Annuals.
I'm not completely convinced by the restoration (the colours seem a bit bright - I preferred the dull-as-ditchwater 1970s originals!), but you soon get used to it, and the commentaries, with people like Dennis Waterman and Garfield Morgan, are very entertaining and informative. You get a booklet with brief plot summaries of all the episodes too. A really excellent set.