From owning both, the Ultra/Kevlar, cream-pearl white is stiffer in the head and a bit less comfy. Btw, the Ultra FPK also came in purple. The Ultra/Graphite, maroon, has a more traditional feel like the Head racquets of the late 80s. All three have more feel and flex than the PS 6.0 or 6.1 that replaced them. Not sure why these Wilson racquets existed? Unlike the Ultra 2 that preceded them or the Pro Staffs. Have a gunmetal grey Wilson Pro Tour that plays like these racquets with a 16x18 string pattern. The only odd spec is that the Ultra/Kevlar weighs 12.6 oz strung while the FPK weighs 12.2 strung.