Ok, so I tried doing two starts from that save file again. This time I think I did a bit better, and I believe that these saves are consistent enough to make a comparison on. I made sure to settle the first city in the same spot, and followed a consistent strategy of tech and city placement, so the differences in these saves shouldn't be due to skill or strategy, just the leader selection.
The big thing that I got out of this exercise was the power of cultural. It definitely helps in the early game. It allowed me to begin improving tiles for my 2nd and 3rd city before the settler arrived, giving them an early boost. I was also able to get a farm up and running on some corn in my 2nd city without the delay, or wasted forest chop, of building a monument. And just as a quirk of the map, with cultural, my 3rd city was connected to the capital quickly, whereas it was left unconnected in the game without cultural.
Being expansionist helped with getting my granaries up, but the difference in worker production didn't seem too significant. I ended with the same number of workers, and similar improvements in both cases.
One thing I did differently from the other saves I've seen is I prioritized fishing, and an exploratory workboat. I believe it will be very important for us to meet other teams early and begin diplomacy. So I made my tech order: Agriculture, Bronze Working, Fishing, The Wheel, Pottery. In both games I finished all of those and was able to put a few turns on Animal Husbandry as well. In the game with Sury I got that workboat out at turn 39, for Mansa, turn 38, so practically the same.
With Sury I settled my 4th city on turn 50, with Mansa the settler was there, and ready to settle on turn 51. The Sury game has more progress towards granaries, and a more developed 2nd city, but I expect after turn 50 the financial bonus is going to come more heavily into play as those cottages come on line. The downside I see to Sury is that the economy is in pretty poor shape with 4 cities, Mansa will be able to dig out of that hole more quickly.
I think that will be more significant than the cultural bonus, and therefore I'm on board 100% for Mansa now.