as a followup:
Zen WERE given a written heads up about line issues before accepting my contract, to which the response was "We will deal with any issues when they arise"
The only reason i switched to Zen was because thephone.coop tech staff, several directors and board members resigned more-or-less simultaneously, taking all technical clues with them
Zen was recommended by industry insiders (they aren't the cheapest - but given the background I want a responsive ISP, not a cheap one) including one of those tech people formerly from thephone.coop
I had assumed that as they use Fritzboxes (I had a 7390 at the time and changed to a 7590 due to the constant disconnections, with no effect), they might be able to diagnose the line better and/or already know of problems in the area (they claim to have other customers here)
Yes, I would go with AAISP in a heartbeat, but I'd blow their caps, so they're a non-starter