I've never understood the safety hate. Besides, the Shield safety is recessed & tiny. Too easy to leave the safety disengaged for those that hate safety features. I like the XD grip safety, which requires a firm grip, and secondary benefit minimal chance of the dreaded limp wrist induced malfxn's.
I owned a Shield40 when they first became available. I was one of the unlucky ones to have the inadvertent mag drop ... mag drop w/o pressing the mag release. I sold it! Now, I have another Shield40 I bought NIB a couple of months back. I've had no malfxns. I also have an XDs45, which I'm more accurate with compared to my Shield. In fact, I've found for me a one-hand grip works best for the Shield.
I will say my Shield40 has a very snappy recoil... this is very subjective. However, I have other .40S&W cal handguns not associated w/snappy turtle. My XDs45 seems to have little recoil for being so small. I should've waited for a Shield9. It is my understanding S&W stopped selling the 40 to 9 conversion barrel. Otherwise, I'd already purchased same.
I bought a used M&P9C, and shortly afterward had the Apex DCAEK installed, which made a world of difference. So, when I bought the Shield40 they installed the Apex DCAEK while I waited. IMO, my XDs45 trigger axn was good from day one.
Regards to the sights, I'm a TruGlo GRN TFO fan. These sights are on both my M&P's, as well as my Glocks. I like the red front sight that comes stock on the XDs.
If, I'd bought the XDs45 before the Shield, then I would not have bought the Shield. I must say many complain, legit concerns, that the XDs fails to go in battery. I've not had such problem. The XDs needs to be racked fully back then let go of slide, making sure to not ride the slide forward.