I'm going Progress right now, feels like capital runs out of tiles to buy too early to use the UA for classical+ wonders if I dump everything into early game snowballing. Being able to rush build settlers is huge.
With a gold and production ruin ('murican scouts being able to spot a ruin over a hill when they're 3 forest tiles away is so satisfying) I was able to get -this- at turn 10, settling on forest. Scout+Monument+Shrine+Worker+75%Settler.
I kinda think that it is better to delay Settlers with Progress for a while, and then use gold in secondary cities to catch up with production. Early cities with progress kill your culture. Also you can grow Capital to like 5 citizen to get some science