I also rode this during the AP/DVC previews last week (on Thursday). It is a great ride...very different, well-themed, and fun.
The Yeti is awesome...huge and very well-done...although it is true you don't get to see him for very long.
I agree that the backwards section is much more intense than that in the Mummy ride at Universal. I actually rode the Mummy the day after riding EE...I had ridden it the year before but couldn't remember how long the backwards part was. EE is much more intense in this respect.
Also, I just wanted to mention that you should try riding EE sitting on both sides of the train. When my friend and I rode, I had always gone in first and sat on the right-hand side. After the first time, I said that during the backwards part, I had trouble telling what direction we were going. She did not have the same experience. The third time we rode, we happened to switch places...she said she experienced the same thing and felt that the right side of the train was more intense, especially in that section.
The only negative comment I have is that it's rather strange to hear screams from the ride echoing throughout the park...especially one like AK. In the recent advent of the evening EMH, I have really enjoyed strolling through the nearly-deserted park at night, exploring paths that don't seem as mysterious during the day, and taking in the silence and peacefulness there. I think I will sorely miss this experience once EE is opened and is running fulltime during the evening EMH.