I was with them for a year on FTTC. I only moved as a FTTP altnet became available, otherwise I would have stayed with them.
The service was fine, not stellar but fine.
They made a billing mistake but they fixed it and were easy to deal with.
They cut me off by mistake (mistaking a request for cancellation of static IP for a request for cancellation of service) but they fixed it.
I think in the year I was with them, I was without service for a day or two.
Speed was as billed.
Latency was a little spikey but ok.
Packet loss was non-existent, as you would hope.
Overall, much better than the Virgin service I had prior but not as good as the BT Business service.
I would use them again if the situation arose.
If it was two
days of no service in a year does sound like a lot, but I dare say it would only have been a part of a day (essentially impossible to say unless you are monitoring the connection). And perhaps that was the misunderstanding re the cancellation of the static IP address.
In the past I'd basically written off even considering Onestream as an ISP (for either myself or others) as I got the impression - or perhaps more accurately the feeling - they were just too cheap and the taking service would result in too many frustrations, but I'm pleasantly surprised to read your account of the service you had with them.
I can imagine things might not be so simple if you have a problematic FTTC line, but then getting such a thing resolved would likely be problematic with many ISPs.
All that said,
their postcode checker currently seems to be down... but then again it is late on a Friday evening!