I have this combination in 9mm. I use both and both have their place in my carry strategy.
To answer your question simply, the subcompact is easier to conceal and will be 'better' for certain types of environments. There isn't much difference between the two but that extra inch of grip is that much harder to conceal.
Now that said, I don't think I would trade one for the other and if I had to pick one, I'm not sure I could... Mostly because I have specific times when I want the smaller gun and every other time, I want the larger gun. Honestly, I would say that you should work with what you have. Maybe try buying some shirts that aren't so form fitting. You can't really conceal any decent sized gun if your wardrobe doesn't allow for it. If, down the line, you think that you have to have a smaller firearm, then maybe look at adding to your options by looking at the subcompact.
One other factor, for me personally, is I find that sub .40 a handful during rapid, SD work. The whole not having your pinkie finger gripping anything is nothing that some training and practice won't overcome, but the round itself is quite snappy and a frame that size doesn't do much to mitigate that. It's just a lot of energy with no factors to help distribute it. I can handle the 26 fine but I'm nowhere near as effective with its twin chambered in .40. YMMV, of course, but I just don't care for that sized frame with that chambering.