I would absolutely take the ability to travel through time. Who wouldn’t? Wouldn’t you like to see the moon landing….live? Maybe check out some chariot races at the Coliseum in Rome? View the Parthenon as it was when it was first built? Pop a couple centuries into the future to see if the United States survived a possible Herr Trumpenfuhrer presidency? The past wasn’t perfect, and there are lot of dangers to do one’s best to avoid, but the benefits would far outweigh the risks, at least to me. I don’t know if my mode of transportation would be a TARDIS or not, but it would fun if it were.