I did wonder if NTL had been hit by a "usenet death penalty", as the last thing I saw on one binaries group was my NFILTER rule picking off a lot of abuse with NTL server msgid's.
And there can be a fault in the feeds for one set of groups, rather than an outage of the whole news server.
The bandwidth issues are complex...
If you use an external server, the all traffic used is external - only the traffic actually used though, but for each person using it.
If you use the ISP server, then it's one lot of external traffic for all groups covered, used a lot or a little.
As for other servers though _ Im beginning to be tempted by the idea of a dollop of Astraweb.
http://news.astraweb.com/plans.html
Unless you seriously expect to do more than 25Gb per month, better to buy it in chunks (no speed limit, no connection limit. no expiry), than on the montly plan.
Clara's 10Gb/month at 30 quid for the year is not bad, but unless you get to use more than 50% of that, the 65Gb Astraweb, and a renewal if needed, works out cheaper.
From what I hear though, Astraweb are not quite division one, but a lot better than many. If you really want superservers, you have to pay super prices.