I'm a big fan of full size duty guns but I think the slim/single-stack striker fired guns are a great thing. They are assuredly a compromise but handguns are an inherent compromise. If they weren't we'd all have an M4 and two-point sling or walking around with a Staccoto XL. Assuming a full grip like the Shield, 43X, 365XL's provide, most people can shoot them as well as a full size double stack. Matter of fact, I think a lot of shooters end up shooting them better because the slimmer grip allows a better purchase (more contact) with a lot of shooter's hands and their associated grip.
They provide even greater benefit if you carry IWB and if you're carrying concealed you should be carrying IWB unless your AOR allows you to walk around dressed like an Ice Road Trucker 365 days of the year. Sawing down sight radius and grip length does little to benefit a person carrying IWB and the trade offs are not worth the benefit when you do it to a double stack frame. Guys walk around looking like they got a boner growing out of their hip or tucked up underneath their belt while forfeiting substantial levels of shootability. The single stack designs allow you to maintain a grip that approximates a full size fighting pistol, a rewarding sight radius, and impressive capacity. All while making the gun more concealable, easier to carry, and (in many instances) easier to shoot.
When you start factoring optics (and I believe all serious hand gunners should be today) the 365 size guns make even more sense because sight radius becomes moot.
But I think the most important thing to consider when you're weighing all these options is to ensure you're being honest with yourself. Be sure your choice in handgun is influenced by objective thought. If you find yourself contemplating a G34 as an EDC, and quickly whittle that down to a Ruger LCP, you're probably just being lazy. And in keeping with the theme of objectivity you should work to establish a standard for yourself. Not some bullschit "most fights happen" theory but a real standard that you can do with a reasonable amount of ammo. i.e. Five rounds from the 25 in XXXX, three rounds from the 15 in XXXX, 7yd line, etc. Establish your baseline with a full size gun that you have a high level of confidence with. Let that be your standard.
Last but not least, if you don't own a shot timer, STFU and go buy a shot timer. A phone is not a shot timer.
Hand gunning is a two pronged discipline. Accuracy and speed. Hitting is step one, hitting quickly is step two. If any handgun choice significantly compromises either of these two things, you've picked the wrong gun and in all likelihood, you are lying to yourself.
