I have had 29 AC flights since January 2006 and only two were delayed due to mechanical issues. Neither of those delays was more than about 30 minutes and neither jeopardized my onwards connection. If I think back through 2005, I flew between 25 and 30 flights that year and had one 5-hour delay.

I realize I don't fly as much as some on this board but there is nothing in my experience over the past three years to suggest that anything is changing significantly.

However, you might take a look at a posting over on canflyer.com about E190 teething problems ...