Not worth it.
You shouldn't be buying your peripherals because they are from a specific manufacturer. That's almost always a very bad idea, as most companies can only do one or two things really good and manage to fuck everything else up.
If you want a G502, get a G502.
Back in the day I had a SideWinder X8, a Qpad CT with a SideWinder X8 art on it and a SideWinder X4 keyboard. Then I got a Zowie EC1 Evo, at which point having bought the X4 was pretty much a waste of money.