I have been using my company outlook for the day because for some reason my left hand menu in Gmail (Apps for my Domain) takes up 3/4 of the screen? I can't figure out why, anyways it gives me a headache.
So I switched to use my Outlook which I maintain because so many people in the company use it. Although I have been clean and sober from Outlook since 2006.
One thing that immediately frustrated me is the lack of threaded conversations. I hated that about Gmail at first, and now it makes me mad to not have it.
It is funny that it is the first feature I can't live without. I have heard others who were frustrated by it when switching to Google.