Simple and effective

Updated: (1.6.6)
Wonderful app. It took 9 days for all of my concerns to be addressed. No complaints now, this is exactly what I was looking for, thank you!

A nice update for the future might be an optional condensed/smaller size.

Pros:
very clean, fast, minimal, unobtrusive
syncs with whatever accounts are on your apple calendar

Cons: (version 1.6.5) Now fixed!
icon is not optimized for yosemite dark theme
cannot add alerts when creating event
the week numbers throw off alignment of the day titles in month view

Will update to 4-5 stars if I see improvement.

JulianState about popCalendar