First let me preface my comments by saying I AM NOT a Gabe Suarez "fan boy".
I do however believe in giving credit where credit is due and Gabe has spent A LOT of trigger time with red dot edc pistols and it might benefit anyone considering a red dot edc pistol to take a look at his book
Red Dot Combat Pistols (currently being offered for a free download to registered WT members).
As to the OPs original query.
I know that it was not one of the options you asked about but if you want one of (if not) the best MRDS for an edc pistol you may consider the Trijiicon RM07.
A properly mounted RM07 with proper co-witness sights is about as "fool proof" an optical system as you can get.
Although it can be turned off there's no need to as a battery will last over a year.
It can be set to auto adjust for lighting conditions or set at one of eight levels.
The likelihood of "accidentally" turning it off is astronomically small as both + - controls must be pressed simultaneously to power it down.
They are so rugged that they can be used to rack the slide if necessary (check the Trijicon NRA Convention video).
And if (like anything made by man) it does fail you have the proper co-witness sights to "finish the job".
Several holster makers currently offer holsters for RMR mounted pistols.
IWB or OWB holster is pretty much a personal choice based somewhat on physique. I personally do not care for IWB holsters but they do work great for some. I've tried several from top name makers (Kramer, Milt Sparks, Mitch Rosen, etc.) and just don't like them.
As far as a C.O.R.E.being hard to conceal, again that is probably a function of physique and dress. I'm about 5' 8" @ 160 pounds and carried a 1911 for years (full size or Commander) and with the proper holster and belt never had any problems concealing them or being comfortable.
I recently replaced my "off the farm" EDC Colt Stainless Lightweight Commander XS (not XSE) with a M&&P 40 PC Ported C.O.R.E. and have no problem easily concealing it.
As sight focal plane length is not an issue with a MRDS a smaller pistol might wok better for some folks without any loss of functionality. A good friend has a RM07 equipped G19 that he carries in a Blade-Tech IWB made for RMR equipped pistols that has a cover for the RMR. In the last year or so he has used it in two 500+ round SI classes as well as thousands of practice rounds and it has never had a single burp. (We compared his G19 today to my PC Ported and it is quite a bit smaller.)
One final thought concerning the learning curve. It has been demonstrated that with proper co-witness sights that curve is very short. My friend with the G19 at first did not have any sights at all and told me just today that he was at first bobbing all over trying to find the dot. He put proper co-witness sights on and now it's instinctive to find the dot. Index the front and rear sights like you have for thousands of shots and the dot is sitting right there on it. Do the "hand off" to the dot and you're good to go.
Take care
James