I am personally running Windows 8.1 for Windows Phone since it became publicly available for the developers. The battery drains a bit faster as you already read over the wide internet. Disabling Internet Explorer in the battery management application helps a lot. I personally also disabled facebook in this application.

You need a developer account with app studio which is free, the paid developer account users will already know how to update. Then you need the developer tools to unlock your phone and you can get 3 updates for you windows phone. On the other site you can also wait if your patient and get the update through your provider.

Pro's from the 8.1 update

Live tiles get transparent so you can set a background

notification area (swipe down and see the notification)

and lot's more you can set and configure for example in the battery management application you can also go in depth what the application can or can't do :)

Another blog from Henk Hoogendoorn is also worth reading go to his blog