Hmm...so I use both my iPhone 7 Plus & Alcatel Idol 4S daily. This is a partial list:
iPhone:
Top feature: Amazing/Incredible battery life
1: Credit Union banking app
2: Health Savings Account App
3: 401k management app
4: Clinic auto Check-In (when needed)
5: Cisco Jabber
6: Overland Bound Talk app
7: Cargly (Car Maintenance App) when needed
8: iMessage with the rest of the family (really like it).
9: Giphy! in iMessage...loads of fun with my daughter
10: Vudu App
11: Flixster Video (Flixster on WM10 is horrible.)
12: Amazon Prime Video
13: Periscope - Watched my son live doing a halfpipe in CO live from my desk in Iowa. (That right there SOLD me on the app gap being a real thing.)
14: Celly - High School uses it for notifications for sports activites.
15: Cigna (Health Ins.) App
16: LinkedIn is much better
17: iOS Support & Upgrade Certainty
18: Continued App Support Certainty
Apps that work well on both:
1: Last Pass
2: Wells Fargo
3: Ring
4: Work email
5: Work Calendar
6: PocketCasts (Degraded App on WM, but ok)
7: WiFi Calling on t-mobile (works well on both devices)
8: WhatsApp
9: Duo Security
+ Social Apps (Twitter, FB, FB Messenger, Instagram)
Things WM10 brings:
1: Live Tiles/UI
2: Work Email/Cal integration via MobileIron is seamless on WM10
3: Bluetooth File Transfer (its awesome when I've needed it).
4: Mentally...my brain 'gets' WM10 much easier than iOS...admittedly, I've only been on iOS since Dec...but I'd prefer WM10.
If you've made it this far...this is my overall assessment. UI is better for me on WM10. I like how it flows, it makes sense and works. Notification center works way better than iOS. In iOS, I still have disappearing alarms if I hit snooze...(no way to shut them off early).
iOS 'flow' of the UI is a mess...an utter mess. However, its very solid. Sure, it has its occasional issues too, ever OS does. Hard to compare speed, but the Apple is definitely snappier in most situations.
If you haven't tried either Android or iOS in years (or ever) there's simply no way to convince you that the grass really can be greener on the other side.
Do I want to switch? Nope, but I was tired of swimming upstream. Obviously since I use both devices, its been a hard transition.