I don't like this style, mostly because they don't "stack".
Here's an example:
* User clicks on the good button, notification pops up.
* User clicks on the bad button. Notification still there.
* User clicks clicks clicks. Alert finally shows, but 5 times in a row.
I was thinking about that as well, I'm game for adding stacking or having the option for the timeout to not finish before showing the next message. This is controllable somewhat by setting the timeout to something less.
Here's an example:
* User clicks on the good button, notification pops up. * User clicks on the bad button. Notification still there. * User clicks clicks clicks. Alert finally shows, but 5 times in a row.