tl;dr: "we remark that all 3 languages provide easy-to-use, high-level and efficient support for parallelism. Haskell has an edge in its rich libraries and aggressive optimisation. Through laziness, top-level parallelism can be specified in a more modular way, minimising the need to modify components and avoiding any notion of explicit threads. Thus, Haskell is the language of choice for minimally intrusive parallelism. F# and Scala provide several mechanisms for parallelisation, some as high level as Haskell’s, some lower level with more potential for performance tuning. Thus, these languages provide a more direct route to controlling low level aspects and can use object-oriented and impure language features."

It would be cool to see a similar contrast between Data Parallel Haskell (http://www.haskell.org/haskellwiki/GHC/Data_Parallel_Haskell / http://www.youtube.com/watch?v=NWSZ4c9yqW8) and others.