With the G5, LG has boldly redesigned their flagship to include new ideas that they hope will capture the eyes of buyers. The biggest and most obvious one is the modular design, which sees the battery slide out the bottom of the handset attached to a swappable module that can be used to add in other features. There's also an all new metal design and an upgraded 2-lens camera system.
Any major computer upgrade generally requires a full software reinstall too. No so if you heed the advice in the guide to Upgrading a Motherboard without Reinstalling. PCSTATS Tips