Paid AI seems to be better. I use it for complicated science. It isn't always right but leads me to new avenues to explore. I treat it as a collaborator to go back and forth with and check whatever we conclude if I can. Humans also make errors and our group checks each other and AI. The collaboration works well. Gemini, Carnegie Mellon and MIT just had a study that indicates spending 10-25% of the time saved checking is what most scientists do. That is an 75-90% time savings.