The leading online used car retailer is disrupting a huge industry.Carvana (CVNA +4.34%) has been one of the most divisive companies on the market in recent years. Critics have said it operates an unsustainable business model that relies heavily on favorable credit markets to survive. Then there are the bulls that point to Carvana being an innovative disruptor that will continue taking share in the used car industry.Let's take a look at Carvana's performance to see which group's views have proven to be corr ...