My company supplies broadband through ICUK. We can choose whether a circuit goes through TalkTalk's network or BT's. Of course both use the same Openreach physical infrastructure. All I can say is:
- Talktalk's network lets us have more control of ADSL connections (e.g. Target SNR)
- Talktalk's network is unmetered
- Talktalk's network is much cheaper
- BT's network has little control of anything
- BT's network is metered
- BT's network is more expensive
As for reliability, there's not a lot in in. I'd say Talktalk's is slightly more reliable. Usually when there's a problem, it's between the customer and the exchange, and whether it's BT or Talktalk, the procedure is just as painful. The quality of the service depends on whether the service level we have, and it tends to be better with talktalk as our package includes 'premium' repairs. However, it mainly depends on whether or not the phone line is provided through us, or a third party. If it's us, it means we can do more diagnostics ourselves and are not at the beck and call of some god-awful phone company who don't listen to their customers.
Overall, it's pretty dire. The sooner Openreach is shaken up and actually provides a good all-round service, the better. We have customers on industrial estates where they can barely get 3mbps (and at one, the contract says they have to use the estate's own expensive slow service, at another, they were persuaded to go for true 'fibre' that's shared with the whole estate, and guess what? they get 3mbps but are paying £100 a month for it!), we have customers in rural areas who need proper service and despite having 3 adsl circuits, still struggle. We have customers in cities who can't get more than 0.5mbps. There's nothing we can do, there's no alternative in most cases, and we have to wait years in some cases to get decent service.
Actually one interesting case was in Wales, near Llandudno, where it took 6 months to get 3 phone lines in. The broadband needed to be supplemented by satellite as it was only 0.5mbps. Then suddenly, we were able to provide full FTTP. That took three months to get installed and running, but it's very expensive, at over £200 a month for 330mbps. They could then get rid of their three phone lines, and use voip. It's the only site out of 50 or so that we provide where we can get FTTP.
So only one out of our 50 sites can get FTTP, and it's too expensive to use at it's 'full' speed of 330mbps. I'm not impressed.