This article suggests that RCEs favor the examiner over the applicant.  The article also notes a study that shows that appeals heavily favor the Applicant.  So why are so many RCEs filed in lieu of Appeals?  Most importantly, an appeal can take a long long time.  It is reported that it can take up to 36 months for a decision to be issued on an appeal.  This time period can be too long especially for technology with a short shelf life or for startups.  Appeals can also be more expensive than an RCE.