I wouldn't personally recommend Daylite nor Windows. Both are buggy and prone to crashing.
Marketcircle's programmers are known for creating poorly written software (like Microsoft). Even their program Billings (which got an Apple Design award) makes stupid math errors even after YEARS of development. It took them 5 years of people literally begging, before they added a simple expense option.
My experience with Daylite has been similar. It crashed 6 times in the first day I used it. It duplicated all of my iCal entries and pretty much destroyed my address book (all of which was backed up, luckily).
I've used every CRM out there for the Mac and none of them are very good, to be frank. Daylite has the most promise, but it needs a LOT of work. Also be aware that it's grossly overpriced and Marketcircle charges an additional annual fee just to sync with your iPhone. Lame.
For now, I'm using the Mac's built-in solutions - iCal, AddressBook, and am using DevonThink Pro Office as my personal database.