I'll be honest, 99% of the Android vs iOS argument comes down to ecosystem and personal taste. Android itself offers very few advantages or disadvantages relative to iOS. The strength of the Android platform really only comes when you attach Google Play Services.
Advantages of Android:
Google Services are king - iOS has everything Google has in terms of Google Services, but most of them can't be made default. Using Google services just feels so natural on Android.
Customization - You can change almost everything about an Android device including the default Apps, the way the launcher/home screen and all the menuing behaves.
Google Assistant - It's just a lot better than Siri. Not much else to say.
Variety of Hardware - You just have a lot of options. If you don't like the way one device does one thing, another device behaves differently. There are all sorts of different camera configurations available as well.
Advantages of iOS:
Privacy - Relative to Google, Apple is far less reliant on your data for profit. I personally don't have a problem with Google having a lot of my personal information. What does concern me is the Chinese phone manufacturers like Huawei and OnePlus. They make stellar devices but sending data back to China makes me a bit uncomfortable. At any point, the Chinese can subpoena your data and Huawei and OnePlus will likely be obliged to send your information to a foreign superpower.
Perks of the Apple Ecosystem - Apple Services are obviously native on iOS, so you can text on your iPad or your Mac. I was at a conference and my Notability notes were directly synced to my iPhone. To me, that's just a huge benefit.
Timely Software Updates - Android is getting much better at this (although I get annoyed as heck by the Pixel update rollout schedule), but Apple builds of new software updates always seem to come at Noon Central Time on launch. Depending on the OEM, Android updates are often few and far between and your phone doesn't usually update to the latest OS until well after I/O and well after the Pixel.
Android Disadvantages:
No Pure Android on a Top of the Line Phone - This is a little nit-picky to me, but Google makes the best pure android device, IMHO, but the hardware is just a step or two behind Samsung or iPhone. If Google could make a Samsung S model phone with pure Google Android, this complaint is null and void. They just haven't done it yet.
Prevalence of Bloatware - 10 years ago when Android started gaining traction, most devices had horrible skins (HTC Sense looked cool but was pretty buggy, TouchWiz from Samsung was trash even when it looked cool). Now, thankfully, most big OEMs have scaled back the customizations within their devices. Now the bloatware is unwanted applications. Sometimes, it's apps out of the box you simply can't delete. Other times, if you buy from a carrier store, it's the carrier software. Either way, the experience is pretty inconsistent and requires scrutiny on the part of the buyer.