I've had a Logitech G602 for about two years now and it's probably my favorite mouse I've ever owned.
Wireless mouse, 8 programmable buttons (6 near thumb, 2 on edge of leftclick button.) What started as a feature I figure I'd barely use became something I can't live without for even basic web browsing. Buttons for history forward+back, tab forward+back and align windows left+right make maneuvering around different windows feel incredible to me.
Setting up different profiles via the Logitech Gaming Software is very easy and super customizable, individual profiles for each game you play with automatic switching between profiles. Options for battery life: performance = higher polling rate with less battery life, endurance = lower polling rate but great battery life. Runs on either 1 or 2 AA's. Get several months out of 2 AA's on endurance setting easily.
I only have a couple issues with it, one being that the wireless receiver can be finicky at different ranges in my experience. I use so many wireless devices all on 2.4ghz range, and when the receiver was plugged into my tower maybe 3 feet away from my mouse, the mouse would sometimes lose connection for a quick second, would happen a few times a month. I have a USB hub right on my desk some 10" from the mouse, and since switching the receiver to that hub I have had 0 problems in about 3 months. Anndd the other problem is that the middle click seems to be the first thing to stop working well under heavy use. My last one worked for about a year and half perfectly before I needed to press harder for the middle click to register. Ended up selling that one and picking up a fresh 602. Been working well so far.