I just got an iPhone 5s and am now using the LTE network for the first time.  I work in 94105 and live in 94122.  In 94105 I've had many issues, but also received download speeds of 10-15 mb/s down.  I'm assuming you guys have some congestion issues.  In my office building, I get 5 bars of 3g but only 1-3 bars of LTE.  At home, I don't really get any LTE despite being right smack in the middle of a major neighborhood of San Francisco.  It is faster for me to shut off the 1-2 bars of LTE and use my 5 bars of 3g, but that's pretty annoying to have to do.  I've been a customer for many years and never had issues with VZW until I tried to use the LTE here in SF.