The Mizuno JPX825 irons succeed the JPX800 and from address look pretty similar. It's on the back of the head that things are different with redesigned cavity structure. The back of the cavity is more 'open' with weight spread in the heel and toe rather than across the back as in the JPX800.
The medallion in the middle of the cavity is centred on the JPX825 Irons rather than being a bar and both these changes give it a very clean look.
Looks aside the performance of the JPX825 iron is just as good as the previous version. They are very forgiving and send the ball on a good trajectory with good feel for a cast iron.The lofts are stronger than most with a 45 degree pitching wedge so you will need to get the gaps covered with a few gap and sand wedges to your putter.
Overall we feel the Mizuno JPX825 irons are more evolution than revolution, but they are still a very good set of irons for mid handicappers who like to have a bit more feel from their irons.