Large compilation time/memory consumption
When compiling the attached test case in the following way:
airpumpkin:integer-benchmark pumpkin$ time ghc -O2 --make -o big Big.hs
[1 of 1] Compiling Main ( Big.hs, Big.o )
Linking big ...
real 1m29.336s
user 1m18.300s
sys 0m6.816s
You can see it takes a while to compile, and uses 640 MB of RAM during compilation.