Here are some great reviews and articles that I have found on DayLite.
Macworld’s buying advice
Confronted with Daylite’s comparatively high price tag, you may decide to piece together a bunch of lower-cost or open source programs instead. Don’t. As an organizer, Daylite 3.7.3 keeps a set of powerful tools in one convenient application.
For a Mac-based small office, I am inclined to believe Daylite is probably the best solution for employees and managers who just want to spend their time working, instead of programming and entering data.
Daylite earns a 4-1/2 moose rating and my applause for making project management less mysterious and more accessible to average folks like me.
The bottom line. For the small-business owner or contractor who wants to get serious about productivity and organization, Daylite is a slightly daunting, but powerful, complex, and ultimately worthwhile, solution.
Opinion: Mac OS X 'an ideal platform' for SMBs
Many business owners are "just fed up" with issues like viruses and crashes that reduce productivity and increase ownership costs, he said. Jetha also pointed out that about 50% of his new customers are switchers -- businesses that once used Windows.
The bottom line is that if you work alone or in a collaborative project environment and need a network accessible tool that integrates with the Apple Mail app and can assist with the management of information, e-mail, events, tasks, people and organizations, there is, I am certain, no equivalent program for Mac OS X.
Daylite 3.1.1 has better project-planning and -tracking tools than a typical PIM and includes the kinds of information workers in small offices need to track and share.