Mizuno MX 200s versus Mizuno JPX HD

I am a female golfer with a driver swing speed around 81 mph and a handicap of 10.  I currently have Mizuno MX 200 steel shaft irons in regular flex.  But I went to a club fitter recently and he suggested the JPX HD graphite irons.  So I took out a set in senior flex and absolutely loved the feel, the ball flight, distance, and consistency.  He said I was right on the border of getting senior or regular flex shafts and I don't know which to get.  I have a pretty smooth swing and he said the senior shaft might give me a little more whip to get more club head speed.

But I don't want to get these and find that they are too flexible in a year. I've been playing almost three years, so I'm hoping I will continue to improve.  And should I be put off because these are super game improvers? Is that a big deal at all?

Id recommend the JPX-800 HDs because of the higher launch and more forgiving design.  The MX-200s are great clubs but there for a more experienced, more skilled player and wont give you as high of a launch as the JPX-800 HDs will.

The JPX 800HD is considered a SGI iron which is more of a beginner - intermediate club.     The JPX800HD also have a cast head versus the forged head in the MX 200.  Some people don't believe there's a difference but most people seem to prefer forged over cast.

At a 10 handicap I'd think the MX 200's are better suited for your game or you might even consider the JPX 800 Pro's or MP53's.  Mizuno's website states the JPX 800 Pro's are for a 4-20 handicapper and the MP 53's are for 0 - 14 where as the JPX 800HD's are targeted at 10 - 35 handicap.  The JPX 800HD is going to be more forgiving but if you're goal is to keep improving I'd think the JPX 800 Pro is a better long term option.  If you're not brand loyal to Mizuno you might also add the Titleist 710 / 712 AP2 to your list of options

The difference you saw and felt is likely in the shafts and I would suggest you try the 800 Pro's or MP 53's with a senior shaft or different regular shaft than you're using currently before you make a final decision.

Are you finding them too "whippy"?  You can always change out the shafts to something stiffer.