I came from the Caravan and more recently the Town & Country. I really miss the huge volume available to the minivan owner. But I had gotten fed up with Chrysler quality control and the dealership (and their service department, but I digress). The styling of Nitro is not my cup of tea and think Dodge and Chysler have really dropped the ball in this regard.
I think the Acadia is a decent vehicle and worth looking at. I was all set to buy the Ford Freestyle and most of those owners panned the Acadia after driving the Freestyle (I have not driven the Acadia). The Acadia just did not offer the mileage I was looking for and frankly GM cars drive me bonkers. The controls are never where I expect them to be - to the point I'll rent just about anything to stay away from them. Ford, Suzuki, Chrysler and Jeep have been much more user friendly. Your mileage may vary as they say.
Ended up with the Edge as it was just more exciting visually than the Freestyle and I was concerned about depreciation (another hit I took on the T&C due to Chryslers over production).
The Edge will haul four people in comfort, plenty of room in the second row which is a big concern for me due to elderly parents. They just don't bend that well anymore.
The back will not come close to the minivan in volume but I can sleep in the back - a big requirement since I need to sleep back there when I take the telescope out to star parties. Just can't do all nighters like back in the college days. I'm about 6' tall so the length and a flat rear was critical.
The Hyundia Veracruz is another one to look at. Never drove it but checked the user boards. The back did not quite fold flat and many owners reported mileage problems which was a deal killer for me. The interior is very well done, exterior is not as nice as the Edge but I think you owe it to yourself to check them out. And that Ford Freestyle. It may cruise down the road better than the Edge (longer wheel base), haul more - just a less than inspiring interior and the sound system is nothing to brag about (the Edge wins here!). The new Taurus X is the Freestyle with the Edge drive train - never tried one.
I think I sit higher in the Edge than in the old T&C and that is a plus for me. I really really like the shorter turning radius of the Edge too. With the van I felt like I docked it when parking. The Edge is more like a sports car to me.
Hope that helps a bit.