I recently considered three row overland vehicles. I narrowed my search to the Toyota Sequoia and the Jeep Commander. I'll summarize a few of my findings that you may find useful.
Toyota Sequoia (1st gen):
The Sequoia has a well regarded 4.7 v8 engine that is found in many Toyota vehicles including the Land Cruiser and the T100 truck (for which the Sequoia shares the same platform). Of the vehicles I considered, it faired well in terms of third row seating (room). However, if you are looking at a Sequoia then look out for frame rust. The severity will be determined by where the vehicle has spent it's life. Toyota issued a recall to replace the frames on many 05 to 08 Sequoias but the job is so expensive that getting them to honor the recall can be troublesome. Also, the issue was just as bad from 00 to 04 but those owners are left on their own and in many cases frame rust leaves the vehicle unusable. It was a massively expensive recall. Dana corp made the steel frames but apparently didn't properly coat them to prevent rust. Google will quickly point you to horror stories.
Jeep Commander:
Ideally you want an 09 or 10 which has all the kinks worked out. The earlier model years had some issues that were mostly addressed with recalls (so make sure the recall work has been done). Especially the ignition key cylinder recall as it was causing electrical issues and random shutdowns of the engine while driving. One thing that was not addressed by recall is valve seats in the cylinder heads. There have been numerous cases reported where valve seats dropped out of the head and caused catastrophic engine failure (in some cases just the head and piston, and in others cases the block was ruined as well). This issue is most prevalent on the 06 to 08 5.7 Hemi engines. The Commander has cramped third row if you're trying to squeeze adults or teenagers back there but for smaller kids it's more than enough room. If you're still considering a Commander, look for one with "Quadra Drive II". This is a 4 wheel drive system made by Eaton whereby the front and rear diffs have electronically controlled limited slip AND locking differentials.
Full size BOF vehicles:
I don't have much to say here other than the fact that they are entering the "too large" category for me personally. When I'm on the trail I like something that is no-larger-than-necessary. This of course comes down to personal taste and planned use of the vehicle. I didn't look into Suburbans or larger Fords too much other than to know the Ford Triton V8 has some known issues with cam phasers (part of the variable cam timing).
Fuel economy: You're typically not going to get great mileage in a larger SUV with 4x4. There are a few exceptions like the Mitsubishi Delica etc. The 5.7 Hemi has been called out for pool fuel millage but I think it's overblown when comparing to other vehicles of a similar size/capability. I have a mini-van which isn't a whole lot better on fuel. The way I look at it is, I can either fit my family in two smaller vehicles, or in one larger vehicle with a third row and get better overall mileage.
What I wound up doing:
I bought an 06 Jeep Commander Limited with the 5.7 Hemi, factory skid plates, and Quadra-Drive II. All recall work has been done. The valve seat issue pertains to this year and makes me a bit nervous so I may at some point pre-emptively swap the heads with rebuilt units that include improved valve seats. Until then I'll make sure to keep the cooling system in top shape (overheating is considered the main cause of dropped valve seats). Overall this was the best bang for the buck in my situation. I have a family of 5 and we fit in it comfortably. My youngest is 6 and my oldest is 12 but I wouldn't' recommend the third row if you have teenagers. I really liked the Sequoias I saw but the frame rust, while not terminal, was evident in the examples I found in my neck of the woods and I'd rather swap an engine then deal with a rotted out frame. Also, the Sequoias tend to fetch more money where I live which would have left me with less money to do the things I wanted to do with it. Additionally the Quadra Drive II 4x4 system in the Commander is a more capable starting point as far as 4x4 systems are concerned.
Hope that helps a bit.