I’m actually a Pentax user and have tried to father pixel shift into the mainline. I use it with the K-1 but started pixel shift with the K3II. I was in the battle here when DPR condemned the K-1 pixel shift. It seemed to gain cred with Sony. It is like so many things with photography that aren’t automatic so you might have to prepare differently. Biggest problem I’ve seen is using a tripod but the tripod is not well grounded – like sitting on a patio with kids and dogs running around it. There was no movement in the area being imaged. So many handheld shots also.
At present, RT has the best pixel shift software. Second would be the Pentax DCU which is terrible to use. They are only ones to handle movement in the scene and RT is many times better.
Another point to make is that pixel shift is not stacking!!! The improvement in the image quality is that everything is real (no interpolation to fill-in the Bayer pattern which actually just moves the noise to the interpolated places).
And another is that if you are going to view after resizing, it isn’t worth the time to pixel shift. Pixel shift gives you better statistics etc for the follow-on processes so that something like sharpening is much improved at the new size.
Enjoy the improved quality but thing before you shoot. Bet John Wayne never said that.