As a proponent of Gmail, I'm always on the lookout for similar, Ajax-based webmail clients. Gmail works quite well, but hasn't ever had a pretty face. Apple recently flexed their programming muscles and released a new version of .Mac Webmail.

This new interface struts all the functionality you see in Gmail, where the page updates and changes without the whole page refreshing. It is intended to work like a desktop application to reduce delays and increase usability.
As beautiful as this interface is, I'm afraid I must admit that it still isn't better than Gmail. If you use a desktop client like Outlook or Mail, and only have occasional need for webmail, then .Mac is a good choice. The IMAP compatibility and 30MB of space will easily meet your needs (provided you already subscribe to .Mac). Otherwise, the costs and limited disk space aren't quite enough for an all-webmail user.
The moral of this story is that Google should carefully review .Mac Webmail (and everything Apple designs, for that matter) and eventually come up with an interface that compares in elegance. Once this happens, my life will be complete (oh, and after I raise a family, too). A larger view of the webmail interface can be found here.
Watch and learn, Google. Watch and learn.

Wy exactly is Gmail better? Just the additional storage? I'm really curious as I'm loving the new webmail interface and functionality of .Mac's webmail. If Gmail is better, I'd really like to know why. Thanks!
It's a bummer that .mac charges - but remember that you're getting more than just e-mail with the subscription (although I must still admit that $99/yr is still a bit pricey for what you get). If price weren't an issue, I'd take .mac over Gmail for the interface and IMAP access alone. Also, I believe that .mac offers 512MB of space, not just 30MB.
As sweet as .Mac webmail looks, it doesn't offer many of the key functions of Gmail, like tons of space, search options, and importing multiple e-mail accounts. I know that you can POP multiple accounts into .Mac, but can you write mail from different accounts?
True, as far as I know you can't write mail from multiple accounts. But you can search easily.
Here is a related article on TUAW.
You actually get 1GB of space on webmail! Just thought I would point tht out.
P.S. Your site is very stylish!
I'm actually not fond of the .Mac interface. Too bubbly, too flashy and not as responsive. I know Google has its shortcomings in interface, but my mother and grandmother and girlfriend use it and were able to just jump right into it. .Mac is likely just as intuitive, but it just shows that Gmail isn't THAT bad and it feels nice and clean.
Also the fact that it's free, and has other cool features like the Calendar, chat between your contacts while they are logged into Gmail, and the online Docs and Speardsheets, I think it's pretty hard to switch to anything else and not feel like you're missing a bunch of useful features.