I've been with Newnet for over 6 years and I stay with them because it's a great service - no problems with usage meter for me at the moment.
Several years ago the usage meter was sometimes going wrong, particularly when recording the night 'off-peak' usage, but has been ok since they revamped it.
I've only phoned customer service once and the response was very helpful although the fault turned out to be a BT problem anyway - Newnet actually phoned me back in the evening to check that everything was working ok. In my opinion Newnet are not the sort of company to 'fob-off' anyone with a problem as you are talking to technical people and not someone reading from a script in an overseas call centre.
The fact that there are not many posts in the Newnet section either means that they have no customers or everyone is happy!
(Nothing special about my router - a second-hand BT Voyager bought from eBay)