Here is my review on Linode. I have been using them for 4 months now. I was referred to them by a friend and I will try to cover the most important areas.
They provide UML VPSes and Xen-based VPSes. My VPS is Xen-based. I use it for:
-Small IRC Server
-Personal file/web hosting
-SFTP/Shell access for myself and friends
-Experiments and installs
Time Used: 4 Months
Setup: The setup was very quick. I ordered and payed and within a couple hours I was able to login. Their system is very cool because upon your first login you build your VPS from absolute scratch. You decide first off which of their 3 datacenters you would like it in, and also your OS choice and configure your swap space and everything.
Service and Network: These areas are very strong with linode. I chose their Dallas location in ThePlanet's datacenter. The network speeds are very fast. Pings are very quick, downloads max out, and many connections can be opened at once without anything noticeably slowing down. The host server I am on is a quad xeon 2Ghz and I'm not completely sure how much RAM it has but I know it is somewhere between 8-12GB. My pages and files always load quickly and the server load averages are never higher than normal. Their linode control panel is very nice since it was made in-house. It provides many customization options and things to play around with. Complete with CPU and network usage graphs as well as and area to start, stop, reboot, boot from another OS image, or reinstall your VPS, their control panel is probably the best I have used out of the 10+ VPS hosts I have experienced. Overall I would say they do a good job in this area.
Billing: Pretty good for the most part, auto-charges my credit card for each month's payment so I don't have to deal much with billing. No complaints.
Support: I haven't had much of a need for their support but I have opened a few tickets for various things. The replies are fairly quick usually within a half hour and many times quicker. The linodes are unmanaged, however, so they are basically there to help out with questions concerning setup or issues on their end. I needed help adding my additional IP and they gave me a few suggestions that put me on my way. Very nice and helpful and pretty good for an unmanaged host. I have used many unamanaged VPS hosts that act annoyed when you send them support emails or simply ignore them. Linode takes things seriously and is very sincere in there approach from what I have experienced.
Overall/Final Look: Overall, I am very satisfied with Linode. They have met and surpassed my needs and expectations as a customer and I would not rather be hosted by anyone else. They are very professional and have a nice setup for provisioning new clients and maintaining their systems. Notifications of scheduled maintenance are always sent out to affected clients, so there are no huge surprises. I would recommend them to anyone and for the money, it's a pretty good deal. I hope you or anyone else may consider them if looking for a VPS provider in the future.