We used to use Dynamics, but it's overly complicated and takes a lot of set up, so that was shelved some time back. I've heard good things about salesforce but have no first hand experience.
I now use Podio which is pretty flexible for project based stuff, and although more of a Task management tool rather than a pure CRM system it still gives good value for customer management. Probably not the best if you're after something purely figures based i.e. if you wanted to export quotes vs sales etc.