It's basically down to extra sync or other features that browsers might offer that might be better for you. As far as rendering goes they all pretty much use the same engine in iOS, so that's not really much of a difference. And actually in case of Safari, as of iOS 9 there are now ad-blocker options too (using 64-bit devices).
From what I've seen it seems that at times some OEM browsers can be better on Android actually (like the Samsung browser compared to Chrome, for example).
From what I've seen it seems that at times some OEM browsers can be better on Android actually (like the Samsung browser compared to Chrome, for example).