There are several different technologies used for ahieving this.
The degree of separation (which is synonym of the security), control over the resource allocation, the efficiency, and the compatibility are things to consider.
Other than the VpsTechnologies used, you should take several common factors into considerations.
- TheOwner?
- TheTechPerson?
- DataCenter?
- ServerSpecs?
- SupportChannels?
- CommunityForum?
- ManagedUnmanaged?
- DiscountAndSpecials?
- PaymentMethods?