I have been on FIOS for over 2 years now and I had no complaints about download speeds.
Howver, upload speeds are unacceptable. They deteriorate after about 1-2 GB to less than 1Mbps. Right now I am trying to backup some files and the speed is 516 KB/sec. Yes, this is KB/sec. I have been trying to resolve this for the last year and everytime it boils down to the conclusion that the speedtest is okay. Download test is usually around the spec, but upload speed test can be all over. Once they hear that I am getting a test over 50% of the spec they are done! I had no luck with getting assistance to resolve why the upload deteriorate so bad.
I am currently on Windows 7 and we have several computers. Mainly use for these tests three PCs directly connected one at a time to the router (not wifi for these tests). All with the same results. The router was so far switched twice with no change. I experienced/tested uploads multiple times to different remote destinations with the same results. One of them is Amazon's S3 service, and other high availability sites.
I am at a loss what to do next. Verizon tech support has provided no resolution with this issue. Period!