Have spent a few hours in the 3rd area. Still loving it. I like that there are companion quests, I've been working on Kai's and his really went places, pretty neat.
Right now I'm running with the animancer chick and the wizard chick, and still tearing things up (on normal) with pistol/grimoire combo + long rifle to switch to.
On the money vs. upgrading thing, I did have a bunch of uniques in my party stash that I was saving just in case I wanted to change spec, but sold a ton of it to buy a flashy new long rifle in Thirdborn. The thing is awesome, but only at close range, no sniping with it kinda sucks. However, being amidst a group of enemies and blasthing them with the rifle, then fast-switching to conjure an ice storm, followed by a fireball, followed by a charged pistol shot to the dome just wrecks things!
Don't sleep on the fast-switch skill in the Ranger tree. The first point speeds up loadout switching dramatically, whilst a second point in it makes any gun not currently selected reload in 3 seconds. Very damn handy for those with multiple guns.