Ive carried both my 42 and 26 in an ankle holster and a Smart Carry, and see no perceptible difference in carrying them, and I still carry my 26 because of it, and for the reasons stated above. I just dont see the need to give up what the 26 offers.
While the 42 is slightly thinner, I dont find its really enough to make that much of a difference. The overall size other wise, is very similar to the 26.
I dont pocket carry simply because my pockets are already usually full of other junk, and the types of pants I normally wear (usually Carhartt/Dickies carpenter jeans), just arent suited for it. The front pockets are too tight, and the rear pockets arent big enough. The couple of pairs of dress pants I have, just dont handle the weight very well either, even with something like my Seecamps or LCP. Even with a holster, it looks like theres a big lump in my pocket. I just find the Smart Carry to be a much better choice all around, and I can carry more of a gun to boot.
I rarely carry anything OWB, and easily carry a 17 IWB on a daily basis, with the 26 as a back up. The 19 and 26 carry just as easily IWB, although the 26 is a little harder to get a hold of quickly when carried in that manner. The 42 is the same in that respect. You reach a point of diminishing returns as you go down in size. Constant practice is necessary for any of them, but the little guns need a little extra effort, and even more so, if carried somewhere other than the waistband.