The G305 looks pretty solid (most Logitech products are), but I have to strongly recommend against a mouse that uses replaceable alkaline batteries. That mouse also does not appear to feature any ability to connect with a cable. This is something I look for on ANY wireless mouse that crosses my radar, after having laid several mice to rest simply because of the cable failing, and nothing else. What I mean to say is, I'd rather buy a wireless mouse that I can replace the cable on than a wired one that I can not.
The Mamba provides this functionality, but at a cost of $20 more than the Corsair Ironclaw, and with a couple less buttons. At this point it sort of just boils down to personal preference, but if I had to choose between the Mamba and the Ironclaw, I'd go with the Ironclaw.
If you are willing to drop that much coin on a mouse it might be worth waiting for a sale on the Basilisk Ultimate. I'm wondering if Corsair will come up with something to directly compete with that product.