If you own an LG G3, it seems that you can get your hands on the Android 5.0 Lollipop software upgrade sooner than simply waiting for it to come over the air. That is, if you own a specific model of the LG G3, the F400S model to be more precise. While Nexus users still await the beginnings of the rollout for Android 5.0, Motorola has started a soak test where some users have reported already getting Lollipop on their devices as part of that soak test. When it comes to the LG G3, we knew the updates were close as there have already been leaked screenshots surfacing in the past week displaying the version of software running on a device.
In regards to the F400S model, a user over at XDA developers has created a thread that includes the leaked Lollipop build of the software, which users can flash to their own device if they have and use that model. It should be noted that this build is only for the F400S model of the LG G3 and no others. Do not attempt to flash it to any other models. The XDA member who uploaded this build(timmytim)mentions that the software is just a KDZ test build, which means it isn't a complete and finished version and likely the builds that are sent out to users officially will be more refined. On that note, users who have flashed this KDZ build to their devices are reporting good response feedback, which means you probably don't have to be too worried about issues.
That said, it's always a best practice to back up anything and everything you find important and don't want to lose just in case something goes wrong. If you don't use the F400S model of the LG G3, builds that are meant to flash on other models will hit the web before too long rest assured. Not to mention that an official OTA can't be far off either. Are you using an LG G3? Are you excited to make the jump to Android 5.0 Lollipop soon? Are you planning on waiting for an OTA update or will you flash a leaked build if it pops up first?