Sony makes FF mirrorless only
Sony does indeed make apsc mirrorless, they actually started with those before full frame. All of the NEX cameras are apsc as well as the newer ones like the a6000. Those are some really great images you have there by the way Gary.
To the OP, one way to think about mirrorless is in the very name...mirror-less. The modern crop of mirrorless cameras like the A7 series and the Fuji are really just 'mirrorless' DSLR's. They can do much or all of what DSLR's do just without the mirror and with an EVF instead, thus the mirrorless moniker. I like to think of mirrorless cameras (MC's) as just an evolution of the DSLR. But most manufacturers have chosen to do away with the traditional shape that the DSLR has evolved into and have come out with a bewildering array of form factors, some sleek and modern and some very retro.
Now one thing to remember, as others have said, is even though MC's are evolutions of DSLR's sometimes the autofocus isn't as good as top of the line DSLR's. That's because the DSLR (and the SLR on which it is based) has had over 30 years of research and development put into its autofocus mirrorbox system. MC's have only been focusing off the sensor for a few short years in comparison.
Of course the DSLR will have a current advantage here, at least for the time being and really in more of the high end models. But for all intents and purposes the mirrorbox is pretty much at the end of its life as far as development goes, whereas on sensor focusing technology has lots and lots of development ahead of it. So AF for MC's will eventually catch up to the top of the line DSLR's and most likely surpass them. The problem is going to be in the refresh rate of the EVF. There may be a wall there imparted by physics that an EVF cant over come when trying to AF on fast moving targets. Not from an AF perspective so much as a 'what can I see in the EVF' perspective. Time will tell.
Another huge advantage of most MC's is the ability to use almost any lens out there. My Sony a7 is for me little more than a 24mp digital back for every lens ever made, especially since I only shoot old legacy lenses. This wont work for everyone in all situations, but it suits my photography just fine. Please feel free to view my a7 folder on flickr for examples of what can be achieved with vintage glass.
α7
As far as I'm concerned those images are in no way inferior to what can be captured with a DSLR, and actually many of them could not have been done with a lot of DSLR's since the lenses I used would have issues when you attempt to adapt them to cameras with mirrors due to the larger flange/focal distance required for the mirrorbox assembly.
Mirrorless cameras currently have many great offerings to choose from and the market is growing all the time. I hope in 2016 we will finally see some serious mirrorless cameras from Canon and Nikon, as well as (possibly) a medium format MC from Fuji. At the end of the day it doesn't really matter what you shoot with as long as your images are coming out the way you want and you are pleased with the results. Your artistic vision and skill as a photographer will factor far more into the final image then whether the camera you have has a mirror or not. MC or DSLR...plenty of great choices either way. Hope this helped.