id go for the callaway x forged
ive got them and love them (ive got the 6.5 shafts in mine)

in my opinion the tayllormade rac mb irons are the best forged irons available on the market, i have a freind who has them with those same rife shafts and every time i hit them it goes flying off the face. they also have a touch of forgivness, cant go wrong with them

The x forged clubs have a slight cavity to disperse the weight to the outer edges. This can actually be a disadvantage to the skilled player. I would say that if you are used to striking the ball pure and know what each shot will do, the Rac MB's are the way to go. The muscle will benefit the better player. Cavities can be inconsistent iron to iron. I have a blended set of mizunos that have a cavity from the 7-3i and muscle with the 8 9 and PW. I found the 8 would fly 178 consitently while the 7 would fly 160. There was nothing i could do to get the 7 farther than the 8. This was because of the cavity. It is behind the sweet spot. So i Had the clubs tested at a demo day and was able to see that the impact point was stronger with the muscle backs, giving the ball better flight and consistent landing areas. The cavity dispersed almost 20 yards shorter. Go with the muscle. Cavitys are ruining golf. They can take away from a good shot. Callaway just released a prototype blade if you want to try a callaway blade. But avoid cavities. They take awayt the pureness of a good shot.