I was getting tired of paying $30 a month (after my one year discount rate of $15 expired) – and a slow connection only resolved by releasing/renewing the DHCP connection daily – for the privilege of Verizon DSL. I got a tip to try DSL Extreme, and so I made the switch, for $15 a month.
A major concern when switching ISPs is the potential downtime. All things considered (including a known issue with the lines at the central office in my town), the transition went OK, a discussion thread is here. One of the highlights of the service was English speaking technicians based in the USA! Both Verizon (in Southern California) and DSL Extreme use DHCP (instead of PPPoE), so no change needed to be done to my modem and router configuration.
They have a good referral program, which gives a $20 credit to the referrer and a $20 credit to the “refer-ee”.