Been using Dataone connection for the last 5 years. Have had lots of issues, but its consistent deliver is good. If it works, it works like charm, else you keep banging your head till their engineers fix it. Time delay is there for fixing a broken connection, unless you know someone in the server room, or some officer at higher up.
The best thing is really unlimited bandwidth at selected tarrifs. No hidden clause or limitation like 512KB till 10GB then falling back to 130Kb.
I recommend it to my friends over other ISP.