The rotation lags on my iPad with calengooI like Calengoo and the developer is really good at helping when there is a problem. One of the things I like about it is the fact that it will let you have a choice about "snoozing" an alarm, as far as the amount of time.
Tried this one and switched from Calengoo. Much more professional looking and works very well!!! See when you read other peoples threads you find help you didn't know you were looking for.
Calengoo, calendars by readdle, pocket informant and awesome calendar support google task integration.I love the stock app but if you end up finding one that syns tasks please post. I am curntly using wunderlist and the stock calendar app or this but would really like it all on one app.