i tried your WP app "My calendar". Please allow me to give you some feedback on my testing. Overall i like your app. It's fast, good readable and has great birthday integration for contacts. Live Tile is realy good.
But there are three points that could be improved in my opinion.
1. In the day view, appointments with short duration, which are close together the subject text is not shown completely. A pinch to zoom could help here.
2. The grid week view is useless, because if there more than 2 appointments on a day there is no way to show them in this view. Scrolling within the day could help or double tap on this day to jump to the detailed day view.
3.There is no default reminder. I have to remind myself, to set a reminder when creating a new appointment. A great Nogo for me.
2 Suggestions
1. A "goto a certain date" function would be great (or i have overseen it)
2. Syncing and integration of google or toodledo tasks would a unique feature
Hope to hear from you, i will keep an eye on your app concerning future imrpovements
Greetings from germany (sorry for my bad english)
(i have send this already per mail, but perhaps there are other user, who want to post their thoughts to this)