It is expensive, but worth it for the true Marvel fan.
We bought the tickets online through a third party vendor and got a discount, plus the convenience fee waived. It's inside the Treasure Island, so you can drive there and park for free.
If you're just going to walk through and look at the props and whatnot, you'll blow this real quick. The true way to make this last 1-2 hours is to actually read everything.
Things like Capt Americas motorcycle, Thor's hammer, and all the various Iron Man suits were really cool and the exhibits very well done.