Speedtest.net Not Accurate?

I have always used this site in the past, but I just recently got fiber in my house and the speeds were registering way lower than I was getting both in uTorrent and getting as a result from Verizon's speed test site.

Speed-test has been telling me anything between 5 and 10 megabits/second download, while in uTorrent I'm seeing the expected 15 megabits/second and also getting that from Verizon's speed test.

The upload has been pretty consistent from all sources.

Anyone else notice something similar?

It depends on how far you are from the test server and how busy it is.

also the java based one is much more accurate than the flash based one

Edit- yes the one you are using is flash based. try going here:
http://www.dslreports.com/speedtest