Apple Watch Series 5
Apple worked out most of the Apple Watch's kinks with the Series 3, and since then the company has been adding improvements that make the Watch a more convenient and phone-freeing accessory.
Solid build quality and design; Always-on display mode doesn't impact 18-hour battery life; Always-on display mode can be disabled; Accurate internal sensors (heart rate; GPS; etc); On-Watch app store is easy to use and useful; Cycle tracking is thorough and discrete with watchOS app
Activity Trends isn't as detailed as it should be; Still no native sleep tracking; Not many Watch-only apps yet; Only works with iOS devices; Expensive; No third-party watch faces