Pros: 32 Functions vs 17, Classic Design, Comfortable for "Claw" Grip Style
Cons: Not as visually striking as the NAGA, A Little Pricey (£69 rrp), Cant update firmware (yet)
First off, the sensor issues people keep reporting are ALSO present on the 2012 version of the Naga, and even then its only on some of the mice; mine is absolutely fine.
The shape of the mouse is much nicer than the Naga, and the slight slant the buttons are on is a design feature; its so you can keep your wrist straight while having your elbow 90°, this helps as it allows you better vision and accessibility of the side buttons without straining yourself. the mouse is also more compact in the sense of its shorter and taller than the Naga; this is perfect if you have a claw grip like me, and its provides much more support than the shallow Naga.
Aesthetically, the device is quite standard - it looks like you would expect a mouse to. Beyond the lighting, its just matte black, no fancy lighting like the Molten, and no abstract shape like the Naga's have; so depending on your taste you'll either love it or just like it. At least you wont hate it like some people do with Razer's stuff.
Feature wise, the G600 has 20 buttons as apposed to the 17 on the Naga and the 11 on the Hex; also the g600 has a GSHIFT feature which essentially has a third button next to the right mouse button that acts as an extra Ctrl key - this by default allows you to double up the functionality of the thumb buttons, making a total of 32 commands from the mouse (double the Naga) - this sounds excessive, but on a game like SWTOR its really useful - even with it it only covers 2/3 of my quick-bars (12 on each)
The software is also really good, its a bit more complex than Synapse, but that only means there are more features. You can switch between using onboard memory or pc-stored profiles, you can reassign all 20 of the buttons to any function you could think of - and there are 3 switchable profiles by default, although you can set application specific ones. You can also set up to 4 different DPI settings - with a maximum of 8200 (compared to the Naga's 5600) and a polling rate of 1000hz (same as the Naga). Lastly it allows you to change the LED backlighting on the thumb buttons, with full RGB 16million colors, full brightness controls, and the option of cycle lighting (it cycles through all the colors quickly) or pulse lighting (a kind of "breathing" effect) with the ability to change the speed of these. You can also turn angle snapping on if you want it.
Lastly, keep in mind is LOGITECH..... so expect the same build quality, reliability and great customer service that's accociated with them.
Bottom Line: If you're willing to put your razer e-peen/fanboyism aside for a more functional yet less visually striking design, the g600 will serve you well
I give it 4½ paddles out of 5, and my own personal "Hooray"