There is quite a big difference in the new TX4 grooves and parallel face pattern which IMO will make them spin more around the greens. And secondly, the GW and LW options have a much better COG placement than the SM5 and earlier. The SW is similar in COG to previous models, since it is/was already in the ideal place for a SW. The GW options have a higher placed COG since it is more likely to be hit higher on the face on full shots and will help keep the flight down a little, while the LW options have a lower COG, more like a PW.

There is nothing wrong with the SM5s, but the SM6s are even better.

Agree with Doug E. I currently use the SM5's in 47-52-56-61. However I do have the chance to take the SM6's out for a round for practice. I like my SM5's and they are brand new but may make the switch to SM6's for high lofts based on the CG locations.