in this test, the Aksiums tested 3 watts more aero than the top Ksyrium ES, and only a few watts 'slower' than many very expensive wheels. Only 5.2 watts less aero than $5000 (AUS) Lightweight Obermayers, which is about the same as using 2 latex tubes!
http://www.rouesartisanales.com/article-4934445.html (takes several seconds to load)
..............................."watts absorbed at 50kph"
Zipp 808....................................18.1
Ritchey WCS Carbon....................19.3
HED Hed 3..................................19.7
Vuelta Carbon Pro WR...................20.8
Easton Tempest II Carbon..............21.6
CKT Splendor...............................21.7
Mavic Cosmic Carbone SL...............21.9
Shimano WH-7801 Carbon 50..........22.9
Campagnolo Bora G3......................23.0
Rose Aerospoke............................23.0
Corima Turbospoke .......................23.1
Bntrga Race X Lite Crbn aero..........23.4
Fulcrum Racing Speed....................23.7
Gipiemme Carbon 5-5.....................24.1
Tune Olympic Gold 2005.................24.1
Shimano WH-7801 Carbon..............24.4
FRM FL-R 23 SD Aerolight...............24.6
Corima Aero.................................24.7
Lightweight Obermayer..................24.8
Xentis Mark 1..............................25.0
Citec 3000S Aero.........................25.5
Shimano WH-R560........................26.1
Lightweight Ventoux/Standard........27.3
Campagnolo Eurus........................27.8
Tune Skyline 2006........................28.1
FSA RD-600................................28.7
Mavic Aksium Race.......................30.0
Citec 3000S................................30.6
Ambrosio X-Carbo........................31.5
Campagnolo Hyperon....................32.1
Mavic Ksyrium ES.........................33.2