I think the Motorola and Xiaomi effects are more severe. It is one thing to compare a $500-600 Samsung S5/S6 vs $600-800 iPhone 6/+. It is a whole other to compare a $150-200 Moto E/G vs $600-800 iPhone.

My intention is not to initiate a debate about which Mobile OS is better, but whether the included bloatware (which you are unable to remove and it's a common practice in Android phones) helps to worsen your experience.

Many mid/lower end phones feel completely unusable without a custom ROM.

There's bloatware out there but for the flagship Android phones typically it's not so bad that it makes the phone unusable for the average user. iOS does not enjoy as big of an advantage in UI/UX as it used to, which is phones like the Nexus 5/6, HTC One, and S5 have decent market share.

Then when you get into cloud services (Gmail, Maps, Google Now, etc.) Android has a clear advantage. So depending on what parts of the smartphone experience a user prioritizes, a logical argument can be made for either platform.

There is absolutely no bloatware on the Nexus-line of devices.