Loading my mail under the new system was taking at least four times longer. Loading a simple text email shouldn't (and doesn't under the old system) lag and take more then just a click to open.
Megan Callahan commented
Anytime I click to open an email or switch tasks on the new outlook, it takes a long time to actually load or perform a task... it's almost like its stuttering. Email content will load, then reload, then reload, then fin...oh wait it reloaded again... oh finally now I can read the email or type an email. Very frustrating to use.
I also see the new interface as sluggish compared to the old one. That is the only reason why I went back to the old interface.