I've had two kids in the back seat, a tall 14 year old and small 6 year old, for 6 hours each way. They didn't complain much and there was enough room in between the two of them so they could have some personal things to keep them busy. The clam shell door storage was great for holding not only drinks but iPods, toys, and books. I like the fact that Toyota installed upper and lower storage spots. Also the seat pocket behind the pass seat is nice, one behind the drivers seat would have been nice. The only complaint was that the little window does not open, but there is a company making a mod for this. http://www.fjfreedomwindows.com/products.html
All in all I think it is a good fit for kids. It's also nice for parents that don't want that typical 4 door SUV. If I had to drive my kids around everyday and they were in and out multiple times per day I might not choose this as my only car. IMO.