No experience with an iPhone, but I would go with either a Motorola or a Lenovo (Lenovo owns Motorola Mobility). Motorola phones have a rather pure version of Android. In our house there are 3 Motorola phones, purchased starting at the end of January 2016 and one Lenovo, purchased during July 2016. All work without any issues. Our neighbor the Electronic Engineer who has worked for a Cell provider for 20 years told me last year that of the last 5 phones he'd gotten, 3 were Motorola and 2 were Samsung.
Samsung phones are very good (I use one), but they do a lot of stuff to the Android OS and are harder to use.
He told me (January 2016) those brands connect to their towers the best.
With any of these brands (Motorola, Lenovo, Samsung) there is a lot of "bang for the buck".
I'd look at UNLOCKED and UNBRANDED phones with a one year manufacturers warranty. That's what we buy in a superstore here. Phones that left the factory UNLOCKED AND UNBRANDED.
I think coming from an iPhone, in this order: Motorola, Lenovo, Samsung.
(My wife bought a Lenovo for my Stepson last July. He says it is exactly like her Motorola phone, but it was a little less expensive).