Editor's Note: TheStreet ratings do not represent the views of TheStreet's staff or its contributors. Ratings are established by computer based on metrics for performance (which includes growth, stock performance, efficiency and valuation) and risk ( volatility and solvency). Companies with poor cash flow or high debt levels tend to earn lower ratings in our model. NEW YORK ( TheStreet ) -- Concord Medical Services Holdings (NYSE: CCM ) has been upgraded by TheStreet Ratings from sell to hold. The company's strengths can be seen in multiple areas, such as its solid stock price performance, revenue growth and largely solid financial position with reasonable debt levels by most measures. However, as a counter to these strengths, we find that the company's return on equity has been disappointing. Highlights from the ratings report include:.