Buy it today and if the other phone works out, return it. It's an OK phone at normal price, it's a great deal at this price.
I think the iPhone 5s battery replacement cost will be 79$ at an Apple Store, unless it's still covered under Apple Care.
I can always find you a deal, but the Moto X is the best thing out there at the moment, though the OnePlus 2 is probably worth the 300$ normal price, even with its quirks.
**BRENT**