Interesting study commisioned by Google on SMB buying behaviours for IT products. In order of importance:

Reliable 73%
Integrates easily with existing systems
Service/support
Appropriate for a company of my size
Flexible  44%
Inexpensive to service/ maintain
Lower cost 37%
Requires minimal training/ education
Company is a well-known, established brand
Scalable
Includes comprehensive training/education
Discounts/promotions
Have purchased from company in the past 27 %