If you're thinking of an XDm in 9mm, look hard at the 3.8" compact version. Very similar in size to the G19, easily concealable with the flush mag (IMHO, add a Pearce grip extension for better control... I'm not a fan of my pinky hanging below the baseplate), and can't beat the 19rd capacity of the extended mag. Little heavier than the G19, and bore axis is a bit higher, but simply a pleasure to shoot with very little recoil. Points very naturally for me (better than a Glock in my hands), and feels like a naturally extension of my body.
I own both a 3.8" compact 45ACP and 9mm, as well as their XDs single stack counterparts. Carry all IWB comfortably, and couldn't be more pleased with my SA family. I like the grip safety, as it's an unobtrusive way to add another active safety mechanism, along with the trigger safety, and other passive mechanisms. I could go on and on... any specific questions, don't hesitate to message. As always, try to hold and shoot one before you buy.