We went today, it was pretty cool. If you went to 2012 SDCC, it's the same exact HoA and Mk42 that was at Marvel's SDCC booth. So if you'd already seen that, not a huge deal.
The additional stuff was a bunch of beautiful, big artwork (movie posters and stills from the movie) and then a 3-4 minute "suit up" thing where you become Iron Man, shoot targets, fly around Tony's shop etc. Not really worth the wait IMO for an adult, but kids love it. Seeing all of the suits close up (and you can get right up to the HoA suits) is really cool if you haven't seen it before.
They also had some other pieces in a case, I believe a coupe of helmets and chest pieces, maybe a boot? Meh, nothing to spectactular there.
Today (Sunday) when we went in at around noon, there was a 10 minute wait to get into the Innovations building, and then about a 45 minute wait in the line to do the "suit up" thing. Once you're in the building, you are free to walk around the exhibit, but there is a 2nd line for the suit up game thing.
But, we walked by later in the afternoon and the line into the building was all the way down the ramp. Not at all worth that kind of wait if you ask me.
I'm loading my photos now, will post some when I can.