I'm with Afrihost with the line rental, main thing that i like is they give you a dashboard to manage your line yourself. I don't even have to log a call, if i want to reset my ports or my lines or sync at a slower rate, i click a button. I can see all my line stats (attenuation etc) on Afrihost's website and up to now, i could fix issues with disconnects and bad performance by using their automatic "wizard" . I specifically had major issues when Telkom upped my sync speed to 6MB/s and it made my entire experience very unstable, constant disconnect or speeds dropping, so i got it to sync at 5MB/s instead, problem solved.
Haven't had an issue where i required a technician yet.