Mizuno Fitting next week

Yeah, I'd also check out the MX-300s as well. Might be able to save yourself some money that way since they're last year's model. Very similar performance to the JPX-800 Pro, and they look great. I reviewed both (JPX-800 Pro here, MX-300 here), and if I had to pick only one, it would probably end up with me, blindfolded and flipping a coin. Not sure if they'll allow you to try them out as well since they're not current, but if they will, I'd give them a shot.Trust me, you won't be disappointed.

 First, I'm a big Mizuno fan, I play the MP-57's and love their feel.  I am not familiar with the newer models, so can't really comment about whether one is better than another.  However, I would strongly suggest that you buy a set based on the golfer you want to become, not the one you currently are.  As you improve, you will appreciate the greater feedback you'll get from a "player's" club.  You want to improve your game, so buy something that won't hold you back.  Anyway, it's something to ask your fitter/pro about.

Don't rule out a combo set with the 53's and 63's

make sure you swing both of the jpx's, the pros and the normal ones. the pros are forged and could give you the forgiveness and consistency you need in your iron shots, with the workability that the normal jpx's wont. 

Definetly give the MP-68s a try too.  You might think that you cant hit a blade, but I think its worth a shot and you might surprise yourself.  Besides, if you are taking lessons and wanting to perfect your swing, nothing is going to give you the feedback that the 68s will.

JPX Pros are really sweet too.  I love my MP-32s but if I were in the market for a new set of irons it would be very hard for me to turn down a set of JPX Pros.  Forged and easy to hit.  Whats not to love about that???