Optimus G (E975) is the Second best device LG has to offer to their consumers. Optimise G is packed with a good configuration of Quad-core 1.5 GHz Krait, 2 Gb RAM and Adreno 320 GPU. Though not the best configuration it can be considered on the better half of the configurations available in the market. To reap the true potential of the device you can root the device by following the following guide. This guide can be used for any firmware (ICS and JB).
If you are still deciding whether to root or not refer this article it may help you make up your mind.
Disclaimer: Perform the procedure at your own risk. This site is not liable to any damaged devices.