I have the Shield 45. The primary reason I got it is because it is just a little bit BIGGER than the 9mm, and my small hand fits on the grip without the extended magazine. I have always thought a 4" Shield would be great, with the grip being molded to the length of the current extended magazines. It could be like a $300 Polymer Commander. Now they are offering a 4" version but I just can't get my brain to accept the magazine being part of the grip frame.
While I like my 45 Shield it gets almost no use. Loaded it is too heavy for elastic pants and if I am wearing a belt I am carrying a normal pistol.