It's a pretty decent action flick with lots of splosions and fx. Story is full of wholes but it was entertaining and fun. Better than T3 IMO.
Without spoiling it, I will tell you that there is a "cameo" that is the most jaw dropping special effect ever. A true double take moment. It was flawless. I really couldn't tell that I wasn't looking at something that wasn't real. It was only my outside knowledge of reality that made me realize this was not real. However, it someone were to watch all the T-movies is a row and having no knowledge of the when they were made or who played the characters, I bet they couldn't tell it wasn't real.