I turned them down because their email servers lost about 10% of our emails when I used them.
I've had a Qwest DSL line since 2000. It was implemented on a Cisco 678 router using CAP modulation. For most of the time I had that modem in service, I had 608 Kbits down / 128 Kbits up. A good download of a Linux DVD distribution could saturate the line at 65 Kbytes/sec. Last month my service was magically downgraded to 256 Kbits up/down. Qwest claimed they couldn't provide faster service on my old CAP modem. They didn't lower my monthly fee when they downgraded the service either.
After hours on the phone, I was convinced that I would need to upgrade to a DMT modem. I went to Radio Shack and purchased the Qwest approved ActionTec GT701R modem. I configured the modem, then called the business office to switch the service to 1.5 Mbits down / 896 Kbits up. That's the limit my ISP can currently service. The service order was processed and I plugged the new modem into the line. It trained to 1.5 Mbits down / 896 Kbits up as requested. I was immediately able to move traffic to the internet. In theory, I should be enjoying download rates that are at least twice as fast as the old CAP modem. In reality, there was still something very wrong. My download rates were 83 Kbits / second. Upload at 190 Kbits / seconds. I called my ISP to complain. They agreed something was wrong.
I just retested my downlink rate against Speakeasy.net using the Seattle, WA server. 1100 Kbits down / 384 Kbits up. That's more like it.