I've been using superbservers (http://www.superbservers.net
) for my fairly high user-base (400k/month) site for a while, and thought I'd write a review.
We've never noticed any downtime, or packetloss, and we consistently push our 10mb port to the limit. The server itself is stable (to the constraits of Windows 2000!), and handles load well.
Support is variable from very fast (couple of minutes) to pretty fast (10-15mins), through their rather good control panel system (which also gives some pretty standard bandwidth info including MRTGs).
I hear they have had some DDOS problems in the past, although I've not seen this cause any problems.
Overall - we've consistently been very impressed with the service.