For email, the Hub works like the traditional BlackBerry email app (in fact, BlackBerry 10 has no separate email app). If you like how the BlackBerry has historically handled email, BlackBerry 10 will be comfortingly familiar. I dislike it: Seeing my replies mixed up in my messages just confuses me as to what each message is and clutters what I perceived as my inbox. Fortunately, as in the old BlackBerry, you can turn that reply display off via a preference setting.
The folder navigation for email is very clunky, requiring a trip to the Hub's account list. And when you file a message from the mail list into a folder, you're often moved to the folder with the message open, so quickly filing messages for later is not at all quick, as it is in iOS and Android. But sometimes, filing a message worked as expected, keeping me in the email list; go figure. Also, messages filed to folders on other devices or computers -- common for those of us who move among a tablet, computer, and smartphone throughout the day -- don't get marked as such in BlackBerry 10, unlike iOS or Android.
To act on a message, tap and hold it ("long-tap it," in Android parlance) to have a contextual menu slide in from the side, then tap the icon for the desired action, such as copy or delete. When in a message, use the More menu (the sideways ellipsis icon) to display those options. It's similar to how Android works.
The Hub's email "app" is adequate, but not as easy to use as iOS's, and a little less easy than Android's.
The BlackBerry's text-entry bluesGiven the BlackBerry 10 OS's messaging focus, I was frustrated by its painful text entry and text editing.
The good news is that the onscreen keyboard is nice and clear, and I appreciate the numerals row at the top -- you even get a standard keyboard's symbols when you tap the Shift key. The ability to swipe the Delete key to delete the word to the left of the cursor is also a nice convenience.
But text selection is very difficult, both to move your cursor and to select a range of text. The text cursor is very faint when trying to position the cursor, and it can be hard to exit that cursor-movement mode. To select text usually requires double-tapping it, but often you get the cursor instead. iOS is way better at text selection, and Android is notably better at it than the BlackBerry 10 OS as well.
Although you can adjust the size of text in the overall UI, you cannot do so in emails, and the text size is barely legible for many people. Perhaps the reason for the tiny text is BlackBerry's desire to seem young. Tiny text is a hallmark of 20-year-old programmers, who don't understand that much of the word doesn't see as well as they do (and don't care enough to let you change the default size). Keep your reading glasses handy.