I understand that the average amateur golfer has trouble hitting the sweet spot (or close to it) on most clubs. This is the exact reason for the development of clubs with cavity backs, speed slots, etc. These game improvement irons provide a bigger sweet spot. Older players (like me) learned to play with blades, since nothing else was available. Our ball striking had to be good or the ball went no where and we were rewarded by a big "rattle" coming up the shaft of our clubs.
I'm trying to get the golfer of today (like my kids) to understand that you get more distance and accuracy by swinging at 80% and striking the ball on (or very close to) the sweet spot of any club, than you do my swinging as hard as you can and hitting the ball off the toe or heel of the club.
I outdrive guys half my age by swinging easier and hitting the sweet spot on my driver. No question correct shaft flex helps, but the biggest distance increase most golfers will experience will be from accurate ball striking and choosing a ball that is soft enough to be compressed by the clubhead speed that you can
accurately
provide. You can buy the right ball, but unfortunately, you can't acquire accurate ball striking by buying a new driver, or reshafting an old one. It takes instruction from a qualified pro and practice time on the range. Boring (I admit) but effective.
The equipment manufacturers will hate me for disclosing this "secret" because it doesn't sell new equipment. But plenty of people won't believe me and will continue to buy a new driver every six months as they are rolled out.
BTW - I'm not immune to the hype. I just looked at a new set of RocketBladez irons. The main reason they are "longer" than most irons has nothing to do with the speed slot or the cavity back - if you look at the club loft on each iron, it is at least one club number higher than most clubs. The 6 iron on my Mizuno MP-64 is lofted at 30 degrees, while the 7 iron on the RocketBladez set is lofted at 30.5 degrees. The RB 6 iron is 26 degrees which is a lower loft than my Mizuno 5 iron at 27 degrees. So of course the RocketBladez seem "longer" than the Mizunos on a club number to club number comparison. On a loft basis the RB 7 iron = Mizuno 6 iron. The RB 6 iron = Mizuno 5 iron.
HOWEVER, if you compare the RB to Mizuno on a loft vs. loft comparison, the RB has a larger sweet spot so it's better for mis-hits, but for sweet-spot to sweet-spot comparison, the Mizuno has a smoother, softer feel and the distance is the same as the RB irons. It all turns on ball striking accuracy.