I'm using a R.A.T. 6 right now, started with R.A.T. 3 many years ago and am yet to find a more comfortable mouse. I don't get the whole obsession with super light mice these days, my guess is that marketing drones want to convince everyone they just need to buy this fashionable thing to be masters of shooters or something. Because, you know, everyone is a master, they just need to spend more on corporate products. Or young people became weaker than actual rodents.
Nice review, although the argument about batteries is just crazy talk. Get a pack of NIMH rechargeables and you have an infinite power source without ever having to plug a cable. I do agree with the fact that side buttons are annoyingly placed, for me the low-DPI button is way too far to the front, I would strongly prefer it to be where the screw is. I like to have it, but the placement makes me use it very rarely. The price is also somewhat too high, I'm going to wait for a sale.