Mail is now a totally different application. Nothing to do with it's first version. Now we have a new interface and a lot more options, and the most important, a better performance.
On of the new features that I love is the way IE opens when you click in a link inserted in an incoming email. To show Apple's fan a real multitasking.
Most of the old Apps have now a new Interface and there are some new ones like Reading List. This App is a must have and use, let's say you found an article online that you want to read but you don't have time. You open the right charm, pick Share and then Reading List.
Then you click Add...
The article is saved in your Reading List and synchronized between all devices where you are using your account.
Once you have read it you can delete it.
Very simple but useful application!