I didn’t like the Ionic for various reasons, primarily its slow and fitbitOS is very much a work in progress. And a year later there an increasing number of posts about some quality related issue, which is classic Fitbit.
Its so darn easy to charge the Apple Watch that battery is not an issue for me. I slap it on the charger while in the morning and evening bathroom rituals. And I don’t like wearing a watch to bed, so I use Sleep Cycle app as both an alarm clock and sleep tracker. And DCRainmaker is reporting that Apple Watch series 4 has the best wrist based optical HR accuracy of all sport/smart watches. You can track sleep on the AW if you load one of several really good apps, I’ve tried it with the original series 0 AW.