Speaking of Scala Pro: "It should be noted that this version performs algorithmic improvements as well, and is therefore not directly comparable to the other Pro versions."
"It should be noted"?! What an understatement! What's the point of going to the trouble of writing a paper if you're not even going to make your comparisons fair? Crazy.
"... the benchmark also used a HashMap<Type, Integer> when it should have just stored a primitive int in Type; it also used a LinkedList where it should have used an ArrayDeque."