Software is eating the world. Or, at least, that's what famed angel investor Marc Andreessen told The Wall Street Journal back in 2011. The past seven years have proven that thesis out, as software-as-a-service (SaaS) companies have come to dominate many industries.The low-overhead, easily deployed model of delivery -- combined with the reliability of sticky recurring revenue -- has meant that investments in such companies have proven very lucrative. The healthcare field is no exception to this rule, and today, two upstarts -- pharmaceutical cloud player Veeva Systems (NYSE: VEEV) and electronic health records and billing specialist athenahealth (NASDAQ: ATHN) -- go head to head.Continue reading