I have a 9mm Shield and love the little thing. Never was a fan of the small Glocks or any of them for that matter since i have been a 1911 guy for many years. Glocks do not point well for me and feel much too thick and bulky. The Shield feels just right. Many IWB and OWB holsters available. I have one of each type and like them both.
Purchased the 9mm since it was available at the time and the .40 was not out yet. I debated over waiting for the .40 to come available but decided on the 9mm for more rounds in mag and cost of ammo. I have shot a .40 since and feel that it is very controllable.

Tom