Shawn Blanc has a nice overview of the latest version of Agenda. Agenda is a solid calendar offering and there are some very welcomed additions to version 4. (What’s not welcomed by me is that new icon.)
The best feature though, is one that Shawn seems to have left out, is swiping from the right edge. Doing this brings up a quick date picker that is really well done and unlike anything I have seen before.
I’m sticking with the iOS 7 default calendar app right now, I like it quite a bit, but I’m glad to see continued development of other calendar apps. Still, none are perfect, but the (hopefully coming to iOS) ability to add travel times is what I am really wanting.