1) Speedtest.net is my primary tool, but I also transfer large files to and from a Linux system exposed on the Internet, and have used iPerf. Speedtest.net has 5 servers within 10ms of my location, and I am able to achieve 600-800Mbps reliably without the Balance One in place, so I tend to use that 99% of the time.
2) ISP is CascadeLink, which is in Seattle, WA, USA. They are a local Gigabit provider.
3) Downloaded and installed beta firmware. Ran test six times with an average of 400Mbps download, and 300Mbps upload. The highest I got during this test was about 450Mbps download, and 330Mbps upload. It seems to have increased a little, but not much.
Other things I noticed/am doing:
CPU utilization on the Balance one is 85-90% during these tests. Seems like there is a bottleneck.
Tests are being run from a wired host directly connected to the Balance One. I can connect this wired host directly to the ISP and get 700Mbps.
Balance One has an AP One AC Mini connected to it - internal radio is shut off.