Waaaaay too many unfunny Terminator jokes and stupid oneliners that really ruin the atmosphere. The plot is just a mess and the character development is terrible. I wasn´t invested in any of these previously established and fleshed out characters, it´s a giant step backwards from Terminator Salvation and remember that wasn´t a masterpiece at all.
To sum up the movie in one picture:
Trollface Arnold says it all...