I have a little over a Gigabyte of email on my email host and they noticed when I started having email problems this week. They politely suggested that that was too much email and I needed to get my email box down to under 250 mb.
I mentioned that my Gmail account is free and lets me have over 2 gigs of space. Well, I just checked and my Gmail limit is now over 5 gigs! I have a fairly small web/email host provider and for them 1 gig is a lot. So, I respect that and also find that inconvenient.
I may be moving to Gmail if I can find a way to use my tokerud.com domain there. While having my email problems, I started playing a bit with Gmail. I normally have all my email forwarded to gmail as a backup and also so I can use the search features of Gmail should the need arise. Otherwise, I rarely use Gmail.
But, I see it is getting pretty good these days. I've noticed many swear by Gmail as their favorite email client, web-based or otherwise.
I like the way filtering works on Gmail. It is easier to set-up. I like labels. I still need offline access but it sounds like that is in the works too.