I use 30Gigs and find it horrible. They email setup is weird. It's made like Outlook, but most of the stuff doesn't work. I can't use the address book to easily add names. I just have to type a few letters so it pops up. Even then you can't click the name, but it tells you have to finish spelling it.
The bulk email delete thing is lame. You have to select the message by clicking on them once. You can't use shift to select a long list of them, so you have to control click each one...one at a time. There are the options to select unread and all, though. Then you drag them to the trash and it decides for a few seconds what to do. Most of the time they end up in the inbox again and I have to select 10 or so email instead of all of them....it takes forever.
The other thing I really hate is the fact that with an alledged 30 gigs, there is no search option. You have to look through each page (which the page thing is also weird) to find email you want. You can't even sort them by something other then the date.