In anticipation for GW2 I bought the G700 and the
G13 about four months ago and I've been using them both for gaming (GW2, D3, Arma2, Borderlands) since then.
I immediately fell in love with the G13, using it with my left hand has become as natural as holding a mouse in my right. The little thumb joystick for movement took some getting used to, but the fact that my ring-, middle- and index fingers have been relieved from juggling both movement (strafing) and skill activation is just great!
The G700 on the other hand (teehee!)...
The quality is great, it's easily one of the best mice I've laid hands on. Nice grip, good weight, high quality material (the surface has a very nice feel to it) and a perfect solution for recharging the battery via USB cable while you continue to use the mouse.
Unfortunately the G700 is a bit too small for my hands (I wear size L to XL for gloves), so I'm always touching/moving it with my fingertips. My hand never really rests on it, and I'm expecting that to cause strains down the road.
The real issue that I have with the G700 however is its software, and this simply can not be overstated: The keybinding program is abysmal!
All of my other Logitech products (G13, G35) can be programmed with the "Logitech Gaming Software", whereas the G700 needs a separate program called "Setpoint", which appears to be designed for standard non-gaming use. In fact, the software pretty much
narrows down your options of keybinding - which makes most of the extra G-buttons utterly useless if you're looking to get the most out of remapping your keys.
Effectively, I'm only using two/three of eight extra buttons in-game, and I certainly don't need a G700 to get that little customization out of a mouse.
The G700 would be top-notch if it were running with the standard "Logitech Gaming Software"; unfortunately "Setpoint" really drags it down.
That being said, I wouldn't recommend buying this mouse, due to its limited use.