Unfortunately they are very marginal over the 140's. A slight wind and energy advantage, you need a lot of HP to get full use of this bullet. I tested these when they first announced in my 6.5 WSM, see data below.
I think that there is a point of diminishing returns on this long bullet thing. I shoot the 147s and I think that they are about the limit in a Creed. I personally believe that the standard 6.5s (Creed, .260 etc) really shine with the 130-140-grain bullets, but that is just my opinion.