I have the same issue - sporadically.
Am on a 75/57 service. Recived a new Actiontec rev I to replace a defective Westell routre. When I test the speeeds I found I was getting 38/4 I thought it was possibly because I was testing from a machine behind a double nat'd router however when I test from a machine directly connected to the actiontec it was only marginally better at 38/6. As the slow upload doesn't really affect me that much I ignored itfor a few weeks.
Last Sunday (3/30) went to see if the same issues were there. All appeared correct now getting 83/39. Tried again today am am now getting 83/12.
Am in the Boston area and get the same result consistently testing with local servers or servers in NY or CHI so have to assume the issue is actually in my home network or between the VZ router and it's connection to the local VZ network. As I haven't changed my local network I have to believe the problem lies with the local VZ network connection.