Better than a lot I've seen. As to checking the specs, I think the only time I've seen folk BLOW UP is over STORAGE. Let's take your phone as example. It specs 64GB but my bet is the user space is in the 50ish GB which is still ample.
I have a lot of phones due to my work but I carry these most of the time.
1. iPhone 5s.
* this person has preferences, but it's mainly a review -- https://www.amazon.com/gp/customer-reviews/RLAEILQAMMX6C
* any few preferences i may have i'll adjust it along the way
* also is there anything to download to check the specs of the phone? to make sure that everything is correct?