Just made the switch from miz MP-58 to AP2's... I've become a non-practicing 8hcp looking for all the playability of my MB's with the slightest bit of added forgiveness and boy did I get it.  These are players clubs (as seen on tour) and will not disappoint.

Side note... at the same time I switched shafts... DG X100's all my life, but on my fitter's suggestion I gave the DG Pro X100 a run. The AP2's added some height (matching like for like loft from my old set) that I have no problem generating on my own, and the flighted DG Pro did wonders to bring things back in line.

CB's are killer.  I got the 714's in feb and absolutely love them.  for my 3 and 4 iron i picked up the 712U's because i read a review about the long irons being little help to most... just learning how to dance with the 712u's and Im loving them as well (especially off a tee on those longer par 3's). I came from playing 1980's png eye 2's so no matter what i hit gave me increased yardage.  The AP2's were nice... i couldn't hit a bad shot if i tried with those lol.  I preferred the feedback of the CB because i try to be a perfectionist.  FOR ME-the mb's were very intimidating.  

Fitter will let you know for sure, but I would go with a mixed set...CB for long irons, MB for 7-9, and (of course) Vokey wedges. 

Another way to go is all AP2. Good enough for Duf, Z. Johnson, Speith, and Haas so why make a hard game harder?

You could go with a mixed set, alot of people do. i use the AP2 and they all feel really good, im confident with 4 through W and im at about a 11 handicap. its all about how they look and feel to you but i dont think you could go wrong with any of them

If you've got the time, try as many as you want.  Since Titleist doesn't push sets (big box retailers may), your set just may not all look alike.  The 712 U is another option for the 4I, as well as the AP2.

Justin,

If you're not opposed to a mixed set, then I would go with MBs for the short irons up to the long irons that you want to replace with either CBs or AP2s. I've seen pros who use a mixed bag with MBs and AP2s, so it's not out of the realm. I've heard good things about the 712Us also. I think it comes down to what you hit well and feel confident with.

I feel like I can give you some good advice with some similar questions you might have.

I've hit all of those clubs, I used to play the AP2's for a few years, I played CB's last year and then switched to the MB's and LOVED them! I'm the same handicap, 13.1, and wasn't sure I was good enough to play the MB's but my scores improved to 70's and low 80's almost every round, with some practice, I found i was playing better golf with the MB's. I think the key was they forced me to take some time and really learn how to hit irons.  I loved the look and even the feel of the MB's. When I started getting better and scoring better I kept thinking about all the posts that say, "if Dufner and Speith and Johnson play them then what am I doing playing the MB's"… you are going to see posts and comments like that all over the place. 

So when the new line of 714 came out last fall i though I should go to the AP2's because if I'm getting better then the AP's should make me play close to scratch right?…. worst decision, I felt the AP's were heavy and not as consistent as the MB's, given I didn't spend years getting used to them but I oddly didn't feel as confident at address and missed the look and feel of the MB's. I thought about getting the CB's but honestly, I think people would be stunned how good the 3 and 4 iron's in the MB's feel and are easier to hit than older blades. I'm no scratch, but playing the MB's all the  way through are making me a better player and the feedback is priceless for me, my game has made leaps and bounds recently and it's been my irons and hitting more greens and learning how to hit the blades that have really been helpful. 

So all I'm saying is you're going to get so many different responses, I see a lot of "mixed set" comments but I'm telling you the MB's in the low irons are unbelievable and if you can't hit them then taking the time to practice until you do will make you all that better:)

I've spoken to a lot of fitters and I don't know if it's true or not but some of them tell me the most common question without a doubt  is "am I good enough to hit blades".  If you are willing to try then give it some time, don't return them the next day because you might not feel you're good enough, spend some time learning to hit them and I promise you it will improve your game, if that's what you're looking to do. 

Just my thoughts, 

Taylor

I was looking for new irons and was choosing between AP2s and CBs. I demoed both and while I was hitting the AP2s longer with a little better consistency, I opted for the CBs. I'm by no means a good golfer, which is why I wanted to improve. Best way to improve your game is not to improve your irons, but improve your swing - and the MBs or CBs are perfect for that. You know right away how well you hit the ball and that response is pivotal in identifying issues with your swing.