I use 'mostly' Opera, and have recently updated to version 10.50, which is quite a change. (lots of new features) I don't know which version you got, as you can always get any older versions of Opera.
   (I can help with the interface & settings of most versions of Opera if there are any problems.)
   I, personally, like 10.50 a lot, even though I have NOT used the integrated email in Opera for several iterations now. Email always did work fine in Opera, and I assume it still does, as they seldom release ANYTHING until it's humming smoothly.

Opera would be a change from the interface you're used to, but it 'might' be worth it.
Firefox would be closer to the 'feel' that you are used to, but as you note, it needs Thunderbird as a companion.

I have no idea if Safari browser is an option, but I wouldn't use it personally.