I think it is compelling. The excitement is in the capacity/size by a top manufacture at a price that is 40% more than shield, but only 12-15% more than G43.
If one looks at S&W shield forums, and g43 forums, there is a lot of talk about trying to get mag extensions, and beyond +1 the problem of those extensions working with target FMJ but having less reliability with self defense rounds. Many people who test out their extensions with Holow Points go back to oem mag only.
I see pre orders from large authorized sig retailers are 500 to 530 with night sites and two mags, so it will bang up shield a bit but the real impact will be G43, if not in decreased sales, some good downward pressure on its street price.
As far as the CAD silhouette drawing, if you visualize it with the flush baseplate, it is smaller in almost every way. lighter than the average too. Also if you line up the upper rear of the grip below the rail the trigger reach is slightly less than the average on those single stacks. And if you look at the way the trigger guard meets the grip it looks like the strong hand can be held a bit higher.
Right now, on paper, this has all of the size benefits of a single 9 and almost all of the benefits of a double stack subcompact 9.
In terms of rail -- that sure looks proprietary. personally I don't care about a rail on a micro compact If I am not wrong there is no rail on G43, shield, P938 anyway, but there is one on xds.
I think this gun will almost certainly hit an amazing sweetspot in the carry market. At 10/12 rounds it also will also pick up some one-gun owners as well, eg female single gun market that shield has a good hold on.
I'm especially curious when this will hit Mass roster, as my jurisdiction uses that roster but not the additional Attorney General constraints (trigger weight, etc). My best guess looking at history, is Mass roster in a two months or so, Maryland roster in six months or so, and California Roster never.