 Spark Therapeutics NASDAQ:ONCE and Krystal Biotech NASDAQ:KRYS are both medical companies, but which is the superior business? We will contrast the two companies based on the strength of their institutional ownership, risk, dividends, profitability, analyst recommendations, earnings and valuation. Profitability This table compares Spark Therapeutics and Krystal Biotechs net margins, return on equity and return ... 