I would definitely go with the iPhone.
Iphone pros:
it plain works, you know what you're getting, pretty good built
quality, emailing is easy as the screen is very responsive, many
apps, customer service is excellent.
Cons: Iphone is a selfish phone.
SE Satio pros:
the camera, friendly phone,
Cons:
i'm not a fan of SE as the charging jack tends to get loose
within a year, tends to be lag. Unless you need the camera, i would
recommend the iphone.
If you are not in a rush, I would suggest you wait a few months
as i believe a newer iphone is coming out