Some of my clients use Merlin. It's compatible with Microsoft's Project and can be used in conjuntion with other Apple apps - Address Book, iCal etc. Whether or not it's best suited for your needs, I don't know. There is a downloadable demo version for you to try. More details here:
I use Daylite and have found it to be an excellent CRM solution. There's talk that the folks at Project Wizards (makers of Merlin) are talking with the folks at Marketcircle (makers of Daylite) and exploring avenues of integrating Merlin with Daylite.