4. Support Capabilities
If the provider does not have a proven track record of support for a significant number of customers using the product, the stability and security of your solution may be put at risk.
When you need technical help, you will typically need it in a hurry. If they will merely pass your problems on to a third party, such as the software producer, you are not going to get timely resolution in general.
If the provider has a support system or newsgroup, have a good look at the contents (if it is not publicly available, ask for a demonstration). If the most recent items on the system are months or even years old, the chances are it is never actually used.