Took the kids (and mostly the hubby) to see this yesterday. We love the first and third Die Hard (the second wasn't as good and the fourth was just into unbelievable territory) and sadly this film follows suit to film No4. If you love car chases and explosions, brilliant - it's for you. If you want a coherent plot, bad luck - it does not appear to have one. I love Bruce Willis and I can kind of see why they have moved on to the Father/Son team up, as he is getting a little long in the tooth to save the day, but I fear if this is the way they are going with the franchise, then we shouldn't have a Die Hard 6 (Should have Died a Long Time Ago).
Bruce Willis (John McClane) does his best with the plot and Jai Courtney (2010 tv series Spartacus) looks pretty muscular in a tight t-shirt, but the laughs are few and far between and we just need more plot. What plot there is (according to IMDB: John McClane travels to Russia to help out his seemingly wayward son, Jack, only to discover that Jack is a CIA operative working to prevent a nuclear-weapons heist, causing the father and son to team up against underworld forces) sadly, is predictable (the Komarov 'twist' I saw coming a mile away) and like the previous film, the stunts take the implausable to the next level.
To be honest, I had more fun playing the 'what have I seen that actor in before?' game, e.g. there was Isobel from the 4400 as a news reporter (though others may have seen her in tv's new 90210 more recently) and McClane's daughter was the bad guy (Royal Pain) in the Disney kids movie, Sky High.
In short, just enjoy the car chases and explosions. 5/10