I have no experience with Hortonworks, but Cloudera certainly tries hard, even though it too has plenty of issues, but then the whole "Hadoop Echosystem" is in

I have no experience with Hortonworks, but Cloudera certainly tries hard, even though it too has plenty of issues, but then the whole "Hadoop Echosystem" is in such fast-moving flux, it's understandable. Cloudera also makes (Apache Licensed) Impala, which IMHO is a pretty cool product. Another company worth mentioning is Databricks, which leads Apache Spark development.