This is great revision of the original expansion set despite this means you have to spend the money again. And this revision makes the old one completely obsolete-so if you're like most of us Arkham players, that was money down the drain. But if you are like most of us Arkham players, you'll still spend the cash to buy this new revision and still think it's a great improvement. If you're a new player-you lucked out! Buy this product as it's pretty well play-tested as none in my group had a problem with this and thought it fixed a lot of issues from the original.
There's a permanent marker that floats around the street area where you can have an encounter with to try to get an exhibit item. This is on top of location cards that may snag you some exhibit items also. And overall, exhibit items are a little better than unique items so with enough players, it almost makes sense to always have someone try to tap this thing for an exhibit item.
The box also comes with a new herald-the Dark Pharaoh with can potentially be a pretty horrific herald. With the expansion set, he makes things pretty nasty and definitely balances out the above mentioned marker. Without the expansion set and with just the original box, he's a hindrance but nothing that should trouble you too much. Regardless, he's a new herald which I always welcome.
So for both new and old players, buy this product. It's a great addition to Arkham Horror.