While it can hardly be considered scientific, I recently held a small engine tournament at 6 minutes per game between my most used engines and was surprised at the results.
I don’t know much about Gull 3 x64, released April 17, 2014, but decided to try it out in a match against the winner of the tournament. Gull only runs on 2 CPU’s so my match pairing it against Critter running on 4 CPU’s is not fair, but still the final result was surprising in that Gull won +2 -1 =7.
On a more reliable level chessengines blog shows the following results:
Houdini 4 wins 3 Super League Season 5/2014 - Jurek Chess Engines Rating 2014.04.21_JCER_Season5_SuperLeague
Gull 3 can be downloaded at Sourceforge.