I also cannot get LTE. In LTE only mode, when I am outside where I get good LTE signal on my google play nexus 5 (capable of 30 megs down), the sprint nexus 5 sees every network except t-mobile's. I'm talking about the search for network menu, it shows AT&T almost always, shows verizon and metropcs' old network (311 660) and also shows sprint's lte network. All but T-Mobile's
So I decided I would swap out the antenna (the piece at the bottom held in by 4 screws that also has the loudspeaker attached to it).
With the sprint nexus' antenna in my google play nexus, everything works just fine in my google play nexus. With the google play nexus' antenna in the sprint nexus, nothings different and I cannot get LTE at all and weak HSPA.
it says "HH.SKU.1.0905" on my google play nexus 5, on the sprint one it says "HH.SKU.1.0816"
both hardware version 11. the water sticker on the sprint nexus is slightly pink, but i havent noticed any other problems
once i get in touch with my buddy who has sprint im gonna test his sim in this and see if i can get full signal LTE or what