Having picked this up on a Deal of the Day on the strength of the premise, I was really impressed at how much was condensed into this scenario.
Written for 7th Edition Call of Cthulhu and set during WWII, I repurposed Station S for a Delta Green one-shot set at the height of the Cold War with very little work required. Obviously I wouldn't want to give too much away here but with a sand-box nature, there isn't the same risk of investigators missing a clue and bumbling around. The NPCs and locations are detailed enough to give you the core to work with but more than enough room to add your own particular flavour. I also like that instead of being overly prescriptive, the scenario presents suggestions of what could be occuring or how to answer questions posed by the players.
For me this product was nearly perfect for my purposes. A premise I could run with for a one shot (although easily enough in here for a couple of games depending on timing and the pacing of your own group) and more than enough structure and detail to act as a foundation. As with any scenario, it will require a good comprehension and plenty of pre-reading and digestion. It doesn't take you by the hand and guide you step by step so may not be ideal for new or inexperienced Keepers (there's the potential for a bit of movement between locations in the vacinity), but there are plenty of notes to help. I like the inclusion of some lines regarding what happened during playtests which gives a far better expectation of the likely things players may do as they inevitably go off piste.
I've only ran this once, but on the strength of feedback from the group regarding the scenario, I'd happily run it again.