VPSville brings up a great point: Which type of server is best for you (in my opinion)
If constant uptime is what you're after:
I would argue that Dedicated Servers have (overall) more uptime than a VPS offering. While they are more expensive (in general, at least $90+ from a reputable provider as opposed to about $30+ from a VPS provider) I would still argue that they are more stable for the following reasons:
1) Dedicated OS with standard install (no templates on dedicated to cause strange quirks with application installs)
2) Dedicated Server hardware is lesser quality than a VPS node (in general) but it is
dedicated. You know exactly what to expect in terms of hardware performance and application interaction with the hardware.
If flexibility is what you're after:
Go for a VPS. They are remarkable in how quickly they are provisioned, upgraded, O/S changed to meet your needs, etc. They are so nimble and powerful for the price. As a test bed or place to host websites, there is nothing better.
VPS's are at the leading edge of any new hosting technology that arises at this time and they are a delight to work with. In general, they are extremely reliable and flexible. Sometimes though, it's comforting to have a dedicated piece of hardware to call your own.
I am looking forward to VPSville's thoughts