Customer service is important especially for tech support. However with some enterprise software, like ERP systems, you achieve the Vendor Lock-In trophy pretty quickly after implementation so you may find this to be something a startup can be very disruptive about: responsive and helpful customer support.
A typical scenario may play out where you have to put a ticket in, wait for a rep to contact you and they ask basic info, log files, etc. then it gets handed off at shift change to another rep, then you need to escalate to a manager who actually knows stuff and can solve your problem quickly.
Not all vendors are like this though. If it is software you have built - a good policy would be to have the software committers rotate into tech support shifts regularly. Can you imagine the joy a frustrated IT admin would have if the customer support person has the right answers quickly? Or utters the phrase "yeah, I helped write that module, let me look at your log files and we'll get to the bottom of this".
