I had one of their (dv) VPS for a while and ran into multiple MySQL performance and data I/O issues.
First off:
Don't get a VPS if you want to put your live site on it. This is why:
A VPS, though it may give you a "dedicated" server environment in which to work, will limit you in terms of RAM, I/O performance and CPU resource allocation.
If you need that type of environment for a live site, then you probably already have a website in the works which will demand the resources of a dedicated server. If you have a "simpler" website with lower traffic and minimal needs to customized apache/php/mysql, you are better off sticking with a good shared hosting provider.
OK, with that said, there IS an in-between choice to satisfy those seeking lower prices, high performance, and dedicated-server-like control.
What I finally landed on is a hybrid dedicated VPS through Wiredtree.com. ***NOT the regular VPS, but the Hybrid VPS***
Why?
... because you get up to 2 *dedicated CPU cores* (you can choose just one, too), dedicated RAM and dedicated hard disk space. It's like a dedicated server, but with half to 1/3 the cost.
I WISH I could post my affiliate link her because I know someone's gonna buy off of it because these guys are THAT good!
Be prepared to spend upwards of $110/month for this service. It is well worth it though and, in many ways, can prove to be better than a dedicated server since upgrades, migrations and maintenance are all quick and easy.
You can PM me if you want a list of a few sites hosted on a Wiredtree.com hybrid VPS.