I swapped the sim from my AT&T iPhone 5 into my new Nexus 5 (using an adapter). LTE registered fine and I thought all was well until I started running some speed tests and noticed really slow speed (under 2MB). I tried messing with APN settings, nothing really worked. If I could get it to fail over to HSPA+ then everything was faster...LTE, still slow. I finally broke down and called AT&T, gave them the new IMEI number, dealt with the hassle of moving my unlimited iPhone data plan over to a regular LTE Smartphone unlimited plan, and thought everything was fixed. But LTE is STILL slow. I've restored the Nexus to factory defaults and I'm starting over now that things should be right on the AT&T side of things. Any ideas? The LTE slowness behaves like it is being throttled...sometimes it will burst above 2MB but then it seems to fall back down to around 2 as though it is being throttled. I'm at work running the speed test and it typically is extremely fast so I don't think it's poor LTE coverage where I am.