Great question Joey. The best place to start would be to visit an authorized Titleist fitter and go through the fitting process.  This will help you find the best set up for your game. Mixed sets work great for some players but others also see a lot of benefits from a full set of the same irons. 

Here's a link to help you find a fitter near you: Find an Authorized Titleist Fitter

I have been using combo sets for quite awhile. The first set I bought was the old Maxfli A10's then a few others before I got some 735cm's played those for awhile now seeing much better play with my 710 AP2's. 

I have been fitted for irons before and I am not sure if they were just not even interested in this or had no idea as to how to do a combination set.  They just did not even suggest that I look at this.

I was just curious.  When I start to look for another set of irons, I will be looking at getting one of the advanced fittings.  I had a fitting from a local place, but i was not overly impressed with it and I am not sure as to how I like my product now.

Thanks,

Joey

From my personal experience as both a PGA Professional and a Titleist fitter I like the idea of a mixed set. I use the 710 CB for my 4,5,6 irons and the 710 MB for the 7-PW. I do have the 3 iron in the CB, but generally keep the 21 degree 909H in the bag as I find it far more useful and I hit it the same yardage as I would the 3 iron.

I agree, go find a fitter and let he/she help you find  the correct set makeup for your game.

Good Luck!