I can't stand it. Right now I can't even login. It just says loading, loading, loading and eventually a dialogue box pops up and says "The action you have requested has failed."
This happens a lot when I'm working in adcenter. I'll click on an ad group or something and nothing happens, it just loads, and then the same message appears. It's pretty aggravating when you have 100's of ad groups.
First they double the number of ad groups I have in order to reach Bing.ca, and now the system is at least 3 times slower than Yahoo's, so basically my job takes a LOT longer than it used to.