I have just "upgraded" to a new Nexus 5 (from Google) from a Nexus 4. The coverage map shows that I have "excellent" LTE coverage in 07432 (LAC:52163 CID:11806021) I have only HSPA and HSPA+. My Speeds are 1.7 Up and about 16 Down. Ironically the N4 was 2.2 up and 20 down.
I called support and they reset the device on the network twice now with no luck. I also went to the local T-Mobile store and was told since I didn't buy it from T-Mobile they couldn't help. This is pure ignorance. This is the same phone regardless of who I paid. The demo on the store floor which WAS a T-Mo Branded N5 didn't have LTE either even though that ZIP 07652 is supposed to have excellent LTE coverage.
I now have an engineering ticket open for 3 days and haven't heard back yet. The ticket number is 4014048.
I would have kept the N4 and not spent the few hundred on the N5 if I thought I would have to continue to use HSPA(+). I have multiple accounts and have been a customer since the network was VoiceStream here (well over 13 years). All I want is to use the service that has been marketed and sold to us.