diff --git a/bench/Bench.hs b/bench/Bench.hs
--- a/bench/Bench.hs
+++ b/bench/Bench.hs
@@ -1,8 +1,11 @@
 {-# LANGUAGE TypeOperators #-}
 {-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE OverlappingInstances #-}
 module Main ( main ) where
 
+import Data.Bits
+import Data.List
 import Data.Word
 
 import Control.Eff
@@ -31,10 +34,28 @@
   return (x `rem` range + a)
 {-# NOINLINE fastIntDist #-}
 
-instance NFData a => Benchmarkable (Eff (State Random :> ()) a) where
+instance (NFData a, Num a) => Benchmarkable (Eff (State Random :> ()) a) where
   run eff n = do
     let res = Control.Eff.run $ runRandomState (mkRandom 0) $ do
-                last <$> replicateM n eff
+                sum <$> replicateM n eff
+
+    _ <- evaluate (rnf res)
+    return ()
+
+b2i :: Bool -> Int
+b2i True  = 1
+b2i False = 0
+
+i2b :: Int -> Bool
+i2b = (/= 0)
+
+bxor :: Bool -> Bool -> Bool
+bxor x y = i2b (b2i x `xor` b2i y)
+
+instance Benchmarkable (Eff (State Random :> ()) [Bool]) where
+  run eff n = do
+    let res = Control.Eff.run $ runRandomState (mkRandom 0) $ do
+                foldl' bxor False . map (foldl' bxor False) <$> replicateM n eff
 
     _ <- evaluate (rnf res)
     return ()
diff --git a/system-random-effect.cabal b/system-random-effect.cabal
--- a/system-random-effect.cabal
+++ b/system-random-effect.cabal
@@ -1,12 +1,12 @@
 name:                  system-random-effect
-version:               0.4.0
+version:               0.4.1
 synopsis:              Random number generation for extensible effects.
 homepage:              https://github.com/wowus/system-random-effect
 license:               BSD3
 license-file:          LICENSE
 author:                Clark Gaebel
 maintainer:            cgaebel@uwaterloo.ca
-category:              System
+category:              System, Effect
 build-type:            Simple
 cabal-version:         >=1.10
 
@@ -21,7 +21,7 @@
                      , mersenne-random-pure64 == 0.2.*
                      , statistics == 0.10.*
                      , vector == 0.10.*
-                     , vector-algorithms == 0.5.*
+                     , vector-algorithms == 0.6.*
                      , primitive == 0.5.*
                      , crypto-api == 0.12.*
                      , bytestring == 0.10.*