To fairly compare the 36 with the 19 and 26 you need to do so with the magazines in since that is how they will be carried. You may find that the 36 and 26 are similar in size if you have the magazines out, but with them in, it really is closer to a 19. A picture is worth a 1000 words.
The 36 was my first CC handgun back when I felt like I needed to carry a 45. It did a good job for me and I never had reliability issues with it. I found it easy to shoot. However once I got the 19, I found that I could carry it just as easily and have 15+1 rounds vs. 6+1. Also the gap between the frame and the magazine would often pinch my pinky during recoil, while not a big deal, it made shooting it a lot not quite as enjoyable as one would like. If I want smaller than 19, 26 is the answer not 36.
If I were set on getting a single stack 45 for CC, I would still pick the 36 over the XDS, but I would rather have a 30S over a 36 if I wanted a 45.
I finally sold my 36 after getting over the sentimental value of it being my first CC handgun. I realized I had not shot it in over 2 years and it deserved a better home than I was giving it. :)