You might find this comparison interesting and useful if you have doubts about what solution would be appropriate for needs of your business - customized CRM or off-the-shelf solution. Each solution, customized CRM and ready-made CRM, has its pros and cons - here's a quick run down.
In this guide you can find out such information as benefits of building a custom CRM software, types and features of CRM software solutions, how much a CRM system costs.