Modern email app with Mbox support

[macstatic]

I'm looking for a modern, streamlined and fully-featured email application to replace my ageing Seamonkey (previously known as Netscape/Mozilla) setup.
I like its ability to have several different "User-profiles" meaning that I can neatly archive my old email and even have several different users on the same computer (without having to set up different Mac login-accounts).

But Seamonkey is, in my honest opinion, getting a bit long in the tooth. Its user-interface is reminiscent of ancient Windows or Linux apps and I'd like to try out something more "Mac like", but with the same (or better) functionality.
Which email apps out there can import and export the MBOX format (so that I can import my existing mail, and export mail when I need to archive, and use Seamonkey for viewing archived messages)?

 

[richard.mac]

Mail which is included with OS X can handle multiple accounts and importing and exporting as mbox. also you cant get more 'Mac-like' than Mail.

 

[themoonisdown09]

I use the Mail application for my Gmail accounts. It's easy to use and has everything I need.

 

[macstatic]

I've been thinking about "Mail", but didn't know it could handle MBOX formatted messages. Cool!

My other concern is that most Apple bundled apps are more "family" type than fully-featured apps. Is this true, or does it generally have the features most people (even mail-heavy users) need?
I haven't really given "Mail" a fair chance, so I'm pretty ignorant here

 

[richard.mac]

Mail is really great. its targeted at consumer users with the ease of use interface but also has really useful and powerful features for power users.

it was the included email application since NextStep which was the predecessor to Mac OS X. http://en.wikipedia.org/wiki/Mail_(application)

Mail has very fast searching using Spotlight, easy rule setting and a great junk mail filter. Mail in Leopard is very smart and useful as it integrates with Address Book and iCal by allowing you to add email addresses and dates from emails. it also automatically sets up your email account when you just type in your email address and password (if youre using POP3) so no need to mess around with incoming and outgoing mail server addresses.

i use Mail and really like it but im not advertising it just telling you its features.

 

[macstatic]

The ability to import and export in the MBOX format is essential for us, so that's indeed good news. But can it also import filters and email addresses from Seamonkey's address-book?
And what about the folder structure of my mailboxes in Seamonkey -can it import that as well?

I'd hate to start from scratch again