I have a g502, it seems somewhat similar? The main issue I have with it is the weight, it's 120g, but that's a lot less than your old mouse. It has cartridges to add an extra 18g though. It's got a massive dpi, up to 12,000, and the sensor apparently doesn't even perform much worse as you get up to ridiculous levels. It's also a bit monstrous. I'd suggest you try it out and see if the fit suits you, but I palm grip it and it works fine. At first I had to work out that my thumb had to rest past the 'sniper' button, before then I was awkwardly bending so I didn't accidentally touch it, but you can tape it/unbind it anyway.
Only issue with mine apart from dodgy software is that the braided cord is coming undone a bit, but I will probably just spam logitech for help/a new mouse if it gets much worse, seeing as it has a 3 year warranty. Doesn't affect the sensor, which is amazing.
Oh the g502 has an optical sensor which is different but probably an upgrade?