I'm referring to calibers bigger than 9mm, but I prefer Springfield XDs. Glocks recoil too much because they aren't optimally balanced. XDs have polymer lower receivers like Glocks, but they have more weight in the upper, so the recoil is significantly less compared to Glocks. I've shot over 5,000 rounds in guns produced by these manufacturers, but it only took me one mag in my XD to tell the difference.
Most police agencies use Glocks because they're reliable and cheap, but I don't think their as good as XDs. The government awards contracts to the lowest bidder, so if police are using it, it's probably cheap.