Can you shoot both before you buy?
I traded a year old Glock 43 for my Shield because I didn't shoot the Glock before I bought it. Once I got the Glock 43 home, I found out its recoil was too "snappy" for me, and its trigger pinched my finger every time it went off. I tried for a year to get used to it, even bought a magazine extension and one of those stretchy rubber things to put over the handle to provide finger grooves. Still, I developed one heck of a flinch because I knew I was going to get hurt every time I pulled the trigger.
At any rate, a couple of months ago my daughter bought herself a Shield, so I asked her if I could borrow it for a day or two and try it out. And I loved it from the first shot. The following weekend I traded in my Glock 43 for a M&P 9 Shield of my own. And because of the rebate, I actually got a few dollars back.
You're right though - I'm not sure about the XDS, but my Shield doesn't feel as solid and well built as the Glock 43 I had. Heck, I can even see daylight through it looking underneath the Shield's slide. But when it comes to
most guns, I'm all about function, not form. I don't mean "function" in terms of it not going "bang" every time I pull the trigger either - the Glock did
that alright, just like my Shield. But every time the Glock 43 went "bang," it snapped my 69 year old wrist and pinched my trigger finger. My shield goes "bang" every time too, and because it doesn't hurt me when it goes "bang," I've gotten over the flinch that Glock 43 caused.
Anyway, that's my advise - shoot both if you can, then decide.
Disclaimer - I'm not knocking Glocks, Glock Fans. My wife loves her Glock 42. It goes with her everywhere it's legal for her to carry it.