There are 2 issues to look at here: Customer Relationship Management (CRM) and Accounting.
Your customer list is your Goldmine, so don't skimp on keeping the list organized via a good CRM program. QB Pro does a great job at accounting, but isn't strong on the CRM part. The CRM program that Bruce recommended does a great job at that, but it's not an accounting program.
Likewise
ServiceMonster is a great Customer Relationship Management tool, but one still needs Quickbooks (or an accounting program) for the accounting portion.
Service CEO is very expensive but it does both from what I know. A combination of QB Pro and
ServiceMonster is hard to beat, but definitely costs more than $200-$500 a year.
In my business we use Peachtree Accounting and Camelot for CRM. It's double the work, keeping 2 databases, but we're used to it and it's not a big issue since we've been using the combo for so long. (2002)
One problem with QB Simple Start is not being very robust in the reporting departments. From what I've seen of QB SS it's not good at keeping a solid Chart of Accounts; and it's only mediocre at CRM. (like QB Pro)
If I had to use only one program for both CRM and accounting it would be Peachtree since Peachtree has the ability to break out customers by Last Service Date and Amount, and export only that info to Excel. It's kind of complex to explain until or unless you've used both programs but I can tell you that QB Pro is not your friend when you try to break the list up by Last Service Date, much less Amount. If you don't mind mailing to your entire list, QB Pro can work as a CRM though.
I had a programmer write a program for me that does allow QB Pro to pull down Last Service Date, but it cannot combine that info with amount so there are some limits. One could code in a custom field for last amount but it must be updated manually each time.