MagiCal is evolving nicely... I've tried every release so far, and the developer is adding lots of useful preferences and options to a cool little app. The biggest weakness--and the reason I'm not using MagiCal regularly--is the problem others have noted with MagiCal's excessive CPU usage.
To demonstrate, I took screenshots of three apps that all do pretty much the same thing, and all of which are free: MagiCal, wClock, and MenuCalendarClock (the latter has advanced iCal integration that will cost you, but you can use it for free otherwise). They all present customizable date and time info in the menubar, and present a calendar when clicked. MagiCal's cool trick is that the calendar can be torn off and replicated in case you want to see more than one month at a time. wClock's calendar is torn off by default and can be repositioned wherever, but it's no longer downloadable unfortunately. MenuCalendarClock's calendar is fixed to the menubar and can't be repositioned.
Magical regularly uses 5 percent of my CPU to do its thing. wClock typically uses 0.5-1.0 percent of my CPU, and MenuCalendarClock typically uses ZERO percent. MagiCal uses 5 percent even if I disable any behavior that might change the menubar information. Here are the screenshot links if you're interested:
I hope the developer will utilize some of the testing tools Apple provides to figure out what's causing the extra CPU usage. I'm sure it'll be fun to hunt that down, and I guarantee you'll win over more users with that than by adding another kind of clock icon (as nice as they are!) :-)
Musings from Mars