From the Freakonomics blog:

Both strategies show that higher-cost hospitals have significantly lower one-year mortality rates compared to lower-cost hospitals. We find that common indicators of hospital quality, such as indicators for “appropriate care” for heart attacks, are generally not associated with better patient outcomes. On the other hand, we find that measures of “leading edge” hospitals, such as teaching hospitals and hospitals that quickly adopt the latest technologies, are associated with better outcomes, but have little impact on the estimated mortality-hospital cost relationship. We also find that hospital procedure intensity is a key determinant of the mortality-cost relationship, suggesting that treatment intensity, and not differences in quality reflected in prices, drives much of our findings. The evidence also suggests that there are diminishing returns to hospital spending and treatment intensity.

Basically what they're saying is that if you go to the budget hospital you're likely screwed.