I felt much more "buttery" hitting at the center. I have played Callaway and Taylormade clubs in the past and they are good clubs, but the FEEL, workability, and playability of the Mizunos are in a different league to me. If you are looking for precision discount golf clubs, the mizuno mx 300 irons is the good "Game Improvement" iron to hit.
I did the mizuno swing test, which confirmed many things and suggested, I would be better off with a blade like iron rather than hybrid. The next closest (higher level) club would be discount Mizuno MP-53 Irons, which I also loved. The MX-300 range is designed to offer similar levels of feel and workability to Mizuno's MP irons (for better players) but with all the performance benefits of the game-improving MX line.
As for the head size and the sweet spot distribution, MX 300 is slightly more difficult than JPX 800. Discount Mizuno JPX 800 Irons which are great clubs too may hit a tad further but the MX-300s are just better clubs when managing the course. I seem to swing easier and have more balance and better rhythm when I play them. I think the lighter steel shafts work better with this club.
The MX-300 irons use Mizuno's Y-Tune technology to provide a full cavity club with enhanced feel and control but in a reconfigured shape. This enables Mizuno to strengthen the area around the toe for more forgiveness. I seem to swing easier and have more balance and better rhythm when I play them. I think the lighter steel shafts work better with this club.
The sole of the discount Mizuno MX 300 Irons is also dual cambered to minimize turf drag and digging at impact. These irons look very clean and are ideal for those aware of their ball-striking shortcomings, but who shy away from anything too chunky. The cavity is 1mm larger in the 3 to 5 irons and then decreases in the 6 and 7 irons. In the 8 to pitching wedge the cavity is covered up and the solid power bar design gives the shorter irons much greater workability and feel.