I've run IDNet on my poorish line for over 5 years. It's as good as I'm going to get. No problems with IDNet apart from some capacity/congestion issues a couple of years back, which they resolved and no problems since. What more could you ask for?
But they can't do miracles. So your line will perform as well as it can. But if your local infrastructure is poor then my experience is you may have to ask whether it is worth it? But you can be sure you won't do any better with anyone else, probably; which is also the point they have made to me!
We see things not as they are, but as we are . - Anais Nin