This is a double, pretty good comparison. Last week I purchased a Ruger 40c and a XDS-45. They are comparable far as size. I got them home, stripped them down and clean factory lube off and used FrogLube on them.
The Ruger comes in a plastic case, with lock, a carry mag, a deeper mag, and mag loader. The pistol is rather light and compact. I loaded it up and put few rounds through with the short mag at 10 yards. It was dead on. I then ran about 100 rounds through it. I had brother shoot it, he had like bear paws. The pistol is dead on. The sights on the pistol are nice, just white dot's but very easy to aquire and looks like the front sight dot is little higher on the post than other's which I love. The report of the pistol, was suprisingly smooth. Being compact as alot of us know, typically report little harder on them. But the Ruger sr40c is nice and easy to shoot all day at the range. We ran several different brands and hollow points through it. It ran all of them with no malfunctions. Alot of people don't like the round indication, but didn't bother me one bit. I am a hardcore 1911 guy, but this pistol is pushing the top of my list. Two other things, the sight's are adjustable too and when you buy you get two, just buy another also.
XDS-.45, This pistol come's in the classic XD platform case with all the usual range gear and two magazines. This is a compact gun in 3.3" barrel i believe, this pistol is light and small. Both the magazines are 5 shot's and fit flush with bottom of the pistol. The pistol has the classic XD agressive grip platform. So, I loaded it up at took the first few shots. Again this is a .45 acp in a micro platform, so yes you will get a report, but suprisingly it is managable. After 100 rounds, Let brother shoot it and he loved it as well. The pistol has a large fiber optic front sight, which is quick and easy to aquire. The pistol is quite accurate and for fun push the target out to 30 yards. The pistol was still grouping well with in the 9 ring of the target. This is a great carry pistol, but not a piece you want to shoot all day on the range, like a 1911. I know it only has two 5 round magazines, but for carry which the pistol was designed for, will be plenty. At home I put the pistol in pocket and came out and talked with brother and his buddy and they was shocked when i pulled it out, it didn't print (yes was unloaded).
Summary- Both pistol's are greatly built and cann't go wrong with either. Brother and I talked and we both actually like the Ruger SR40c better. It had little better recoil management, grip felt better and the trigger felt alot crisper to me and him.