The new Forest Fane is completely awesome. Hard grand sword-master darklings and assassins, as well as the normal backstabbers. Big new ogres. A priestly Black Agnes with spells that will pwn you. A nice setup for archers to destroy you. Tons of creatures sneaking at crippling striking you (though, it is annoying that the one spell that you could use to avoid an ability drain has been nerfed.) Very nice set-up. Very attractive.
The two chests are a bit messed up, though. We slugged it through. actually died at the end. Fought a zillion creatures. Got to the chests, DC 44 and 42. Inside, we find... 119 fang, traveller's boots, scrolls: magic weapon, mage armor, PfElement. Considering I think that place is as hard, or harder, than the shadow caves, that's a little paltry.
If you're going, don't go without a priest. And some freedom of movement.