I've been with InterServer.net for a little more than a year now, renting out a dedicated server from them for my own personnal uses (Game server/FTP/SSH etc) and I thought I would write up a quick review about them.
When I first joined InterServer they had a deal on dedicated Atom Servers for 39$/mnth. The price was right and I've always wanted to play around with a dedicated server, so I said why not.
In the year that I've been there, the support has been fantastic. Most tickets are replied to in about 5-15 minutes, except for emergency reboots which are usually done inside of 5 minutes. Uptime has been virtually perfect.
Even though I had paid for an unmanaged dedicated server, John and his team were always happy to point me in the right direction when I was having OS configuration issues. (I am far from being a Linux pro.)
I have since moved (about 2 weeks ago) to a higher plan of theirs (Core2Duo), and again, the performance is great.
I had a quick issue with a sluggish performing hard drive when I switched over, but it was fixed within a few hours.
All in all, InterServer seems to care about their customer's satisfaction. The prices are a steal, and the performance and uptime are fantastic. I would recommend them to anyone.