I've put thousands of miles into S300 cranks. I personally could not tell the difference in stiffness between S300s and Omniums. If you want a 130BCD GXP setup, S300s are great. However, you can get the Miche Primato Advanced cranks for the same money which are lighter and 144BCD. You will have to use a square taper JIS bottom bracket, but I prefer square taper systems for fixed gear riding anyway. I'd decide what style bottom bracket you want to use, then get either the S300's or the Miches. Sugino RD cranks are inferior to both the S300s and Miches in every way.