This is a really great buy and I wouldnt hesitate to download it, its visually appealing, simple (once you figure it out) to use, and is going to make keeping track of grades and projects way easier. A few things that its missing from the UI that would make it vastly improved are: a) An option to only view from certain hours of the day in the weekly calendar view so that Im not opening my calendar to midnight every time, which is slightly annoying; b) A daily calendar view, and c) Multi-gesture support (specifically to enable the ability to swipe left and right to view different calendar weeks, as is supported by the native iCal app in Lion.)
Overall a really great app, nicely laid out, simple to use, with just enough features that its helpful but not overwhelming. I would definitely recommend. :)