So I just got Series 3 today and replaced my Series 0. The difference in fluidity is absolutely staggering. I didn’t feel like the Series 0 was unbearably slow or anything, even on watchOS 4, but the Series 3 makes it seem ancient in comparison. Like an iPhone 3GS against an iPhone 8. I haven’t activated LTE yet, just wanted to share my very first impression from switching. If you have a Series 0, the Series 3 is a serious upgrade.