I don't have any hard data but I would say they are a little more forgiving. I had a 718 T-MB 4iron with a KBS Tour shaft. I now have a U500 4iron with the Hzrdus smoke shaft. Due to the different shafts it's hard for me to say what is attributable to the club head alone. That said, on center hits are noticeably farther. Hope this helps.

The new ones are bigger. The U510 has very big sole while the U500 is abit narrower but I’d say is bigger than the old TMB. Think the blade length is bigger.

I had a chance to demo a U-510 1 iron. That was only because that was the only LH option brought to the Invitational. I only carry through a 6 iron as I've struggled to hit a 5 iron consistently. But I was still able to hit the U-510 consistently off of the turf and as far a 19H. While the launch was too low, that is a lot of forgiveness for someone that shouldn't even have an 20 let alone a 16 degree iron in their hands. I'm still thinking if I got fit for a 22 degree how it would fit in my bag.

I have the U510 2 iron. I'm getting a very high ball speed and very narrow dispersion, even with misses. I put both good and bad swings on it and the results are the same: high, long baby draw.