Hands down.  Really: it is the most frustrating, clunky piece of sh1t I have ever had to deal with to get email - and I go back to the days of logging in via DOS to UCTVAX and UCTHPX!!

The latest insult is this - which I get after a banner which says my mailbox is corrupted, and needs to be rebuilt, and that this may take a few minutes:

It has been saying that for 30 minutes....

I have had enough.  I am already in the cloud (yes, looked at from both sides now, thank you B-), I have my Gmail account (retroid.raving@gmail.com, seeing as you asked - thanks, Vernon!), I have imported all my addresses and I autoforward my mail.  Frak Gwise.  FOREVER!!!!!