moosejaa
Mr. Inconsistent
SLDR are different irons altogether so I'm not sure I'd compare them in that way (i.e. in terms of 'improvement'). They are smaller, likely shorter, and less forgiving and made to be that way.
SpeedBlade in my opinion was an aesethetic upgrade - looks and feel. Maybe some tiny differences in performance, but I didn't really see them.
Thanks Hawk. I saw something about the SLDR irons being geared toward the 10-15 handicap player. I also saw a comparison between the Rocketbladez and Speedbladez with the Speedbladez getting a very slight edge. Never know how subjective those reviews are though.