An Improvement?

I got these Burner 2.0's to replace my TaylorMade Super Steel irons that I have played for a long, long time.  I thought that maybe I needed' to get up to date technology wise and enjoy the benefits that new irons would bring.  Well, after 3 rounds and several range sessions, I'm not sure that I've made a good decision.  Maybe I'm just not striking it as well as before, but with the new irons I'm experiencing much more difficulty in just hitting a straight solid shot consistently.  I'm much more likely to slice it now even with short irons, that just didn't happen before.  It seems I have to be much more conscious of getting the face closed now.

The new club feels lighter and they are R flex while my old clubs were stiff.  I hit the new one on a simulator and the salesman told me that the R flex would be right for me although I had my doubts.  Distance on my good hits is really not any better either.  So, I must admit I'm disappointed.  I hope it's just a matter of getting better acquainted with them.