Personally, I could not hit the thing to save my life. However, that doesn't mean it's a 'bad shaft', just that the properties of the shaft (bend profile, kick point and torqure) may just not fit my swing.
Here's what Tom Wishon said about the Nunchuk shaft on his forum (www.wishongolf.com)
In terms of the bend profile design of shafts, the Nunchuk is pretty different. What I am talking about is the combination of bend profile frequency measurement numbers for shafts. If you were to spend some time studying the Bend Profile measurements of many different wood shafts in our Bend Profile software program, you would see that most shafts follow one of a handful of common, similar progressions of bend profile measurements.
Sure, they vary a little when you look at all the numbers, but with a bit of study, you can see that most all of the wood shafts out there are created within a somewhat narrow range of these measurements for how the shafts graduate from their butt to the center to the tip end of the shaft. Shafts for avg players have their typical graduation of Bend Profile frequency measurements, shafts for a little better player have theirs and shafts for good players have their progression of frequency measurements.
The Nunchuk deviates a lot from these typical norms when it comes to its bend profile measurements. It starts out at the butt end as VERY, VERY STIFF compared to any other wood shafts - FAR more stiff than any of the X flexes that are out there. Then it drops down in the middle part of the shaft to be quite flexible in relation to its butt stiffness design. And after that it ramps back up to being very, very stiff in the tip section.
Their concept is that the flexible middle section has the effect of softening up the butt stiffness so that together, the butt + middle section then won't play either as stiff as the butt is on its own or as flexible as the middle section is on its own. But still, for as stiff as they have created the butt section to be, even with it dropping down to being flexible in the middle, it's still a very stiff shaft when you talk about its overall stiffness design.
What's tough for most to believe, and count me in that group, is Nunchuk's claim that this one bend profile they have created is a good fit for all golfers. That to me is a ridiculous statement. Now in all fairness, it is true that many golfers, chiefly those with early to midway release moves at the ball, could play and hit the ball the same with any shaft flex/bend profile. So from a pure distance and launch angle standpoint, it is true that a very wide range of golfers would all end up hitting the ball no different for their swings with a Nunchuk than with a hundred other shafts of different stiffness design. This is because we believe completely that the performance of a shaft with respect to its launch angle/trajectory only shows up for golfers as their release gets later and later and later in the downswing.
On the other hand, it is true that most golfers, regardless of their handicap or swing characteristics, will feel differences in impact solidness from shafts of a greatly different stiffness design. It is a fact for many golfers that if they hit the ball on center with a club that has a very stiff shaft, the feeling of impact will be much more DEAD or BOARDY and unresponsive than if they hit the ball on center with a more flexible shaft.
In this sense, I do believe that most people who would hit a Nunchuk shaft, and meaning most golfers with a swing speed under 100mph who also have an early to midway to even slightly later than midway release would sense that this shaft creates an unsolid feeling of impact with the ball.
But, what I will say is that the fact that the Nunchuk shaft does open the door to thinking about really upsetting the norms of the usual and typical progression of stiffness design in a shaft. I think the NUnchuk as it is made is a viable shaft for a strong, high swing speed golfer with a late release - but not for anyone else than this. However, some other radical varations on the releationship of the butt to center to tip stiffness could be found that might be acceptable to other golfer swing types.
So when looking at shafts, make sure you understand their characteristics (weight, torque, bend profile, kick point, etc) so you can understand what type of shaft fits you and your swing the best.