The Hawaii-Five-O reboot is the second show in two years to come out of the brainstorms of CBS programming executives (NCIS:LA was the first) that works as a show and as a cast.
The O'Loughlin/Caan banter is really well done and makes the show purr. That's not to say I don't appreciate Grace Park being on the show, but I hope she isn't type cast as a hard ass (since her previous role as Cylon number Eight on the Battlestar Galactica reboot.)
It is hard to explain why this reboot is working so well, but no matter, it is working.