ServInt only does VPS hosting and by some estimates are the largest provider of VPS hosting. They manage "several" of their own data centers in Virginia.
I currently manage a website hosted by ServInt, and having worked with their tech support, I can say that they have one of the most technically proactive staffs around -- ie., they propose and then implement solutions for your problems. Got a complex website and need to add more technical expertise to your team? These guys are a good choice.
Differentiator: They can grow with you. Their entry level VPS is priced at $50 per month and would make a good first step after low-cost shared hosting. Their high-end enterprise solutions top out at around $1000.
Their biggest sales pitch is their fully managed support.
Liquid Web also offers dedicated server plans.
A Small Orange is an Atlanta, GA based Web hosting company that has built its reputation on unparalleled customer service. They cater to small businesses who prefer to work with small, personal vendors.
The only downside to ASO is their lack of a big VPS plan. Their packages top out at a $125 756Mb RAM plan. ASO is ideal for the shared hosting customer looking for a more stable solution (ie., guaranteed system resources), but not requiring the power of a dedicated server.
Differentiator: Public forums. Having their pre-sales and support forums be publicly accessible is the ultimate in transparency. It also probably keeps the staff on their toes, which results in superior customer service.
Slicehost is a popular VPS provider for the tech savvy developer.
They can grow with your blog or website. The entry level plan starts at just $20 for a 256Mb VPS (hardly more expensive than low cost shared hosting), and their biggest VPS slice tops out at 4Gb RAM for $280.
Plans: $50 for 256Mb guaranteed RAM; up to $100 for 768Mb RAM.
Pros: Dotster offers both Windows and Linux VPS servers. Low starting price ($35).
Cons: No server above 512Mb RAM. Larger websites will want 1Gb or more of RAM.
Prices: From $35 for a small Linux VPS (256Mb RAM) to $100 for the top Windows server (512Mb RAM).
Pros: Lowest starting price of $15 for a decent sized VPS (256Mb RAM, 6Gb disk space).
Differentiator: Cheapest VPS hosting around.
Reliable VPS Web Hosting Companies
Web hosts that specialize in virtual private server (VPS) hosting
VPS stands for "virtual private server". When you get VPS hosting, you share the server hardware with other websites but you are allocated a dedicated share of the system resources. A VPS plan is a good bridge between low cost shared hosting and the reliability of a dedicated server.
With a VPS, you usually have full root control of the server. It's like you have a dedicated server. If you don't have the system administration experience in-house, it's best to go with a VPS hosting provider that also gives you a "fully managed" server.
Here is a list of reliable Web hosting companies that specialize in VPS packages.