A lot of the reviews point out that the G100s and G300 are small mice so I'm not sure they'll suit me. The G600 looks promising shape-wise but I'm not all that convinced about the quality, legitreviews points out that the surface has got scratched and worn just during the course of their review testing.
Just want to mention that the surface on my G600 still looks like the day I got it, the review you link mentions that it got scratched while being in a bag, and this will happen to pretty much all mice with some sort of surface coating(meaning most, if not all, gaming mice and the majority of decent office mice.)
My G600 has seen a fair bit of use, and the coating holds up far better than the stuff used on older mice for normal use. Mine's white, which might hide some of the wear, but I can't actually see any wear at all on it. And when it hasn't been sitting on my desk it's been sitting in a drawer with a bunch of other mice, still no scratches.
As somebody who's own 2x Logitech G600's, each one connected to a different PC, the G600 is solidly built. There's been no scratches from regular use, no noticeable fading after 9 months. Logitechs claims of the mouse being built for durability has held up so far.
I also have a Logitech G602, my personal favorite mouse with a balance of features that will fit most users scenarios.
As for Razer, I have gone through
2x Razer Boomslang 2000's
Razer Copperhead
2x Razer Habu
Razer Lachesis
Razer Imperator
Each mice has failed in < 3 years for one reason or another or has developed a significant flaw or issue that caused me to stop using it.
Every previous Logitech mice aside from the 3x gaming line mice that I own still work, the only reason I got new mice was either higher DPI, more buttons, etc.
So take my user experience as another sampling point.
Razer not built to last
Logitech is built to last longer than Razer, and especially the gaming line.