I've read the many comments on the lack of lumbar support and owners suffering from back problems with the Prius. Although I've only had my car for a month, we rented one for a long trip before buying it. Neither my SO, who is 6'2" (with back problems), nor myself, 5'8" had a bit of a problem with the seats and, on the contrary, found them extremely comfortable. Could the height of the person have anything to do with this? Perhaps only shorter people?
Beats me, I'm about 5'8" and don't find the seats that bad. I've driven my Prius from San Jose to Vegas and back (8+ hours, each way) and from San Jose to LA 2x (5.5+ hours, each way). Perhaps some people just like to complain...
I'm 5'5" and find them to be comfortable enough. The only drawback I find is that when I have the seat position so my leg comfortably reaches the gas pedal, the steering wheel seems a bit too far away. But it's not that bad. I still love my car.
Some people are built "funny" or have had situations in life the predispose them to being uncomfortable. I'm used to sitting on rocks, logs, or other garbage that was not ergonomically designed for human comfort so I find the Prius seats perfectly fine, even for 13 hour drives. Well, nothing is comfortable after 13 hours but you know what I mean. I'm 6'3" and 170lbs so maybe I just blend into the car and others do not?
I'm 6'1" and find the driving position as comfortable if not more so than the '08 Highlander Hybrid Limited I was driving. No foot, knee or back problems at any time during my hour commute.