Great question. Invariably when researching different models you come across the forums where some critical part of the car has failed costing the owner thousands to repair, and yet after a while it becomes clear that every model has its share of lemons. So then you are back to cobbling together information from a bunch of distributed sources which is a pain, and prone to bias from fans of particular models etc. I would love to see something in this area and even better, a startup that can undercut the ridiculous mark up of second hand cars from dealers, but still offer cars that are guaranteed not to be lemons.