We had issues in 2017 with Sun Transfers. Getting through customs was quick (coming from the US). We waited at the designated meeting spot and watched while other deplaned passengers were getting picked up. We waited 45 minutes for our driver to arrive, and he seemed like he had no idea that he was supposed to be there. There was only two of us.
We also used Barcelona Day Tours, but we did not use them for transportation from airport-hotel or hotel-port. We booked them for a tour of Barcelona and Montserrat. They were really nice people, and the gentleman I worked with prior to arriving was super helpful.
Maybe Trip Advisor has reviews of transportation services.