The new 5.1 udpate seems to be more of an under the hood update. There are not really any huge overhaul features here, however there are several new things that will make this update well worth it. One of the biggest changes in 5.1 is the added support for dual sim card support, and HD voice support. There is a new device security feature that won’t allow any would be thief to use your phone unless they have your google login information. They won’t even be able to factory reset it without your log on info.
There are also several theming features that really polish the look and feel of Android in this build. Essentially this is the way Lollipop should have been to begin with.