To me, "mission based" and "play to find out" are not at odds. Just slightly constrained. Combined it reads like this, "play to find out how the players do the mission." You give them a mission. Now we play to find out how that goes down. That's The Sprawl.
For missions only this is somewhat true. Never having run a The Sprawl campaign before I fell back into my bad DnD habits of over-preparing (shrugs off remorse about his 80 pages DnD campaign PDF) – especially preparing the How? was a bad mistake – If I know how I want the players to get the thing, I'm not playing to find out, am I?
I ran two one-shots before, where I obviously couldn't over-prepare, since I was going to learn the teams composition while playing – This actually went pretty good, thinking back. Maybe it was because of the type of mission, maybe it was because of minimal preparation. We may never know (probably latter).
For a campaign which isn't just unconnected mission after mission The Sprawl doesn't help you at all I find. The only thing that stays between missions are the Reporter-Clocks, Corp-Clocks, and the characters experience/gear.
There can't be much of a story development, if the players don't get a say, about what mission to do next, and the players can't even decline a mission the GM gives them (well they can, but then it's session over, as I mentioned).
There are some simple hacks around that, like asking your players at the end of each mission:
What do you want to do next? Do you have an idea of what to do next/Please pick one mission of these three 6-word sentence-missions I've written down.
But it's a hack. The book doesn't include that.
My current intention is very much to run a campaign with meaningful player input for the missions, rather than nothing changing at all in between the missions, except some minor: "Hey, Corp X is at 2300 – Here's me showing you the barrel of the gun".
RE: Running The Sprawl: First impressions