Bought the new 2012 Toyota Yaris (newly redesigned; only out a few months). The car has extremely uncomfortable front seats (causes back ache after 1/2 hr of driving). I have not seen any other complaints regarding the front seats of the Yaris yet, so I assume that the Yaris prior to the 2012 redesign does not suffer from the same problems. The 2012 Yaris seats have poor ergonomic design (no lumbar support); hard, thin foam; cloth tented over the foam; and the head rest is angled too far forward. These are similar problems reported by Toyota Prius owners.

Update from Feb 4, 2012: Had leather seat covers installed which included additional foam padding. This substantially improved the seats. I added some additional foam padding in key areas to improve lumbar support and even out concavities in the seat, finally fixing the problem.

I can't believe Toyota would design and install such unergonomic seats in one of their vehicles. Who were they designed for? The hunchback of nortre dame?