Question about iron sets?

Last year, after having played for 20+ years, I finally decided to get more serious about getting better. I got lessons for the first time in my life (3 day golf school), part of which was a professional fitting. I currently have Cleveland TA-5 irons (4-PW) that I had 3/4" added to when I got them. The professional that measured me recommended a steel shaft (I have about 100-105 mph swing speed), a 39.5" shaft for my 5 iron with standard loft and lie and oversized grips. I'm 6'5" and have always felt I needed longer shafts, but never got measured. He also recommended either Ping or Taylormade irons because he said, they're among the lightest weight irons made. He watched me swing my clubs and asked if my back bothered me, and while I don't have back problems, I do find it my back getting more sore after playing than it used to (part of that is getting me getting old). I tend tend to slice my mishits and have had a lot of trouble hitting my irons for about the last year and a half (after I tried to totally rebuild my swing on my own).  I'm currently about a 25 handicap, and at one point, was down to about a 17 (pre-swing rebuild).

I'm ready to get my irons and have been shopping around looking at the different Ping and Taylormade sets. I've always been a Nike guy, and was looking at the Nike VR irons, but after my experience at the golf school (I highly recommend it, by the way) I'm focusing more on what was recommended to me. I'm having a hard time narrowing my choices between the Ping G15, G20, i20, Anser, and the TaylorMade RocketBallz, RocketBladez, and the Burner 2.0. Does it really come down to personal preference, or is there any real difference between these clubs? Thanks again to every one!

I may be in the minority here, but when it comes to iron play, I recommend sticking to what you are familiar with.  As I've posted in other replies, if you are used to a specific look, feel, and sound from one manufacturer, it's very difficult to change to another - unless these specific attributes are less important to you.

Not sure that I agree with the pro that told you to go with a specific OEM because of their weight characteristics as each manufacturer provides customization options that can get you what you really need.

One final note, and I think this is most important, don't compare today's iron lengths to older irons.  Your TA5's have much softer lofts than today's irons, so comparing the distance between the TA5 7-iron and the TM Rocketblades 7-iron, is an unfair one.  You may have to compare the TA5 6-iron, to the Rocketblades 7-iron (lots of opinion around this, so be ready for some contradictions).