TripAdvisor says that taxis can be unreliable/hard to get in Sitges. We'll need to get around to a few sites. Has anyone used Uber in the area? Other recommendations?
TripAdvisor is wrong. The Sitges population (+28000) relies and has always relied on taxis. The fleet is 40 taxis (plus 40 more in the nearby town of Vilanova i la Geltrú). To my knowledge, the number of Ubers in that area is negligible.
Where exactly do you need to go? There are also buses.
Excluding the big cities (Madrid and Barcelona, mainly), Uber, Cabify, Bolt...are not very present in Spain and most of the time taxis are the best option (fares are regulated by the city council and are totally safe and controlled). In many places, Uber and the kind cannot do internal city rides (Bilbao, for example), only from town to town.
We booked a taxi in advance through Cabify to get from our hotel in Sitges to the airport. There are also taxis that hang out by the train station, which is centrally located.