I use G510 before.
I was using ADIA64 to monitoring my GPU & CPU OCing on the lcd screen.
Plus, SirReal, C2DtoG15, countdown clock for instant noodle, song name display, ingame info, ingame binds, internet traffic...etc, just make my geek life more easier.
I'm using my G110 in the office, G-keys, headphone & usb jack helps me alot.
G510 is a very useful tool if you use all the functionality.
If you have a chance, go try some mechanical switches, see if you like it.
I brought my first mechancial keyboard 4 months ago.
I still trying to sacrifice between features & faster, more comfortable keypress response.
Can't tell you is it worth. Cos I still a newbie.