Yeah, I love those kinds of missions. If you have high exploration rank and good rep, you'll make more on the fare. Currently, I'm getting about 1,000,000.00 cr./1000 ly for passenger missions. But yeah, the real money comes from exploration data.
On my last trip to Sag A* I made 200,000,000.00 cr. counting mission reward and exploration data.
Right now I'm doing a mission that will end up being about 36 kylies round trip with about 900 jumps. I think I'm a bit better at exploration these days (finding candidates for terraforming, etc.).
It will be interesting to see what I make on data this time.