That's arguable either way I think. The Police were formed in 1977, and while U2 may have been technically together a few months earlier, when Larry posted the message in October of '76, the Police had their first HUGE hits in Roxanne and Cant Stand Losing You (and a full length LP to boot) in 1978 (well early 1979 in North America).
U2 didnt officially become U2 until March of 78 and it would be almost another year before their first official single U23 would be released. By the time their first LP Boy was released in October of 1980, The Police had released 3 critically acclaimed albums: Outlandos d'Amour, Reggatta de Blanc and Zenyatta Mondatta, which included amazing tunes such as the two mentioned above, as well as Next to You, Message in a Bottle, Walking on the Moon, Bed's Too Big Without You, Don't Stand So Close to Me, De Do Do Do, De Da Da Da, Driven to Tears, etc...
The Police's journey up the charts certainly came before U2's, so I would say that the Police were hotter before U2 was.
U2 is still my favorite tho!!