I have a lifetime carry permit, but do not exercise it. Some of this has to do with my profession (which is not carry-friendly), and some with my wife's comfort level (which is improving). I do keep a handgun in a locked case in my vehicle. It goes in the nightstand at night.
I have a S&W M&P9c, which I got before the Shield started to become more available. It was a compromise option that I felt was more concealable and ergonomic, for me, than a G19 or G26. If I could do it over (or, if I could get spousal permission now), I'd get a G19 and an M&P 9mm Shield. Shield for concealed carry and G19 for everything else.
I shoot the G19 better than the M&P, but the latter is much more comfortable for my hand than the former. The Shield, which I have not shot, I would expect to match the ergonomics of the 9c that I have, but with a thinner profile (which, if anything, will be an improvement).
If you're actually going to carry regularly, you need to research and try different holster arrangements. Even though I don't carry, I do have a Galco Kingtuk IWB holster (so, I could carry if I were so inclined). If I get the opportunity to switch to the G19 and Shield combo, I will likely get a Raven Concealment Systems setup for both. Lots of quality holster makers out there, and several different carry options (appendix, belly band, ankle, pocket, IWB, OWB, small of the back).
While I don't currently carry, I have the ability to do so if circumstances warrant. Down the road, especially if I get a Shield, I may carry daily anyways. We'll see.
One other thing to consider when carrying are safeties. Key feature for you to consider on a carry weapon. Preferences vary. Many CCW folks prefer no external safeties. Others prefer an external safety (grip or thumb). Others still prefer no safeties and carry unloaded, with magazine in pocket or otherwise concealed. Personally, I'd be more inclined to carry regularly if I had gotten my M&P9c with the thumb safety. Google "Glock leg"