David Smith gives us a nice roundup of feature improvements in Microsoft R Server 9.1:
Interoperability between Microsoft R Server and sparklyr. You can now use RStudio’s sparklyr package in tandem with Microsoft R Server in a single Spark session
New machine learning models in Hadoop and Spark. The new machine learning functions introduced with Version 9.0 (such as FastRank gradient-boosted trees and GPU-accelerated deep neural networks) are now available in the Hadoop and Spark contexts in addition to standalone servers and within SQL Server.
I have been looking forward to these.