Given a pattern of "90:00", if someone types '2:' it will presently reject the ':'
What would be better is a pattern of "9?0:00" where the '?' indicates an optional character. Then if someone types "2:" it could recognize the optional character and automatically insert a space. 
  The same would apply for dates, e.g. "00/00/0000", would become "0?0/0?0/0000" and then you could type "2/4/2015" and it would insert the spaces
  The benefit of this is that the user can see what format is expected but can also type in a faster manner

For certain web pages that require editing speed while using masked input controls, it slows down data entry when a user clicks on a masked input expecting the text cursor to be where they clicked when instead it highlights the entire text box.