I picked up a 2010 GX460 late last year for less than what similar year & mileage (<100k) 4runners were going for, for many of the reasons posted in this thread.
Its done what I wanted it for, mild trail and dirt road exploring and being the family truckster for getting my kids out there. Its very comfortable for the long highway miles required to get to where I want to go to explore. It handles surprisingly good for what it is - I credit the chonky sway bars that come with the KDSS system, they work great for keeping the car under control on curvy mountain roads, and yet with KDSS active don't seem to limit off road performance. The third row is genuinely useful with my younger kids (3 and 7), its great to be able to put up the back row and put the kids back there when we have family in town and be able to take one car. I'm guessing when the kids are in their teens it'll be too small, but I doubt I'll have this car that long. I also like that its less common than the 4runners, especially the earlier non-spindle grille version.
Some downsides I'm not seeing presented here. Not deal breakers for me, but something to be aware of when choosing the platform:
- Tire clearance is limited compared to 4runners. They come with 30.5" tires. A 32" (265/70R17) seems to be the limit for the stock spare location, and on my truck had a surprising amount of rubbing on the fender liners with that size. 33's are doable. A few people have done 35's with major trimming of body mounts, fenders, running boards, etc.
- Fuel economy isn't as good as most forum dwellers pretend it is, but its probably not much worse than a loaded 4runner. I've seen 18 on a mostly slow highway trip, generally loaded for camping and heading to the mountains is 14-16. Fuel tank is 23 gallons, and larger tanks are very expensive but probably worth it if its mostly a long trip vehicle.
- The side opening back door is dumb. I cant think of any reason its better than a hatch unless you have a tire mounted to it ... which we don't in the US. Luckily I don't live where I need to frequently parallel park. The saving grace is the rear window opens separate from the back door.
- Approach angles are bad for the 2014+ spindle grille facelift. The 2010-2013 body style has a 7+ degree better approach angle. Aftermarket bumpers solve that issue but for what I do are totally unnecessary.
- The engine really sucks to work on. Its clear to me after changing the alternator myself that this chassis wasn't really designed for a V8. There's not much room to get to anything under the hood, the rest of it (suspension, driveline) is OK. My steering rack is starting to leak so I looked at the factory service manual to see what the replacement procedure is. Step 3: Remove the Engine. F that.