There is not set category of people/players that each club model applies to. The best way to find the correct club for you is to go through the fitting process. When you work with a qualified Titleist fitter, he/she will have you hit shots with your existing club(s) to get a set of baseline numbers to start with. Then you will hit shots with various head/shaft combos to see which fits your swing the best. Use the search tool and enter "Titleist Thursdays" to get to the page and find an event near you and schedule an appt. (it's free).

Go to the club information on this site,all the information and specs are listed,along with videos.
AP1 cavityback iron,offers more forgiveness on miss hits.
AP3 from the latest reports simply amazing.
T-MB the look of a blade with distance and high launch.
I would see a fitter and get fitted for the right clubs.
Your fitter should be able to help you find the right clubs and shaft combination for your game.

I can't tell you which is for whom. But I can tell you to get fitted and they will show you your stats. Find a "Thursday" fitting and they are free.